… | |
… | |
39 | F<README.embed> in the libev distribution. If libev was configured without |
39 | F<README.embed> in the libev distribution. If libev was configured without |
40 | support for multiple event loops, then all functions taking an initial |
40 | support for multiple event loops, then all functions taking an initial |
41 | argument of name C<loop> (which is always of type C<struct ev_loop *>) |
41 | argument of name C<loop> (which is always of type C<struct ev_loop *>) |
42 | will not have this argument. |
42 | will not have this argument. |
43 | |
43 | |
44 | =head1 TIME AND OTHER GLOBAL FUNCTIONS |
44 | =head1 TIME REPRESENTATION |
45 | |
45 | |
46 | Libev represents time as a single floating point number, representing the |
46 | Libev represents time as a single floating point number, representing the |
47 | (fractional) number of seconds since the (POSIX) epoch (somewhere near |
47 | (fractional) number of seconds since the (POSIX) epoch (somewhere near |
48 | the beginning of 1970, details are complicated, don't ask). This type is |
48 | the beginning of 1970, details are complicated, don't ask). This type is |
49 | called C<ev_tstamp>, which is what you should use too. It usually aliases |
49 | called C<ev_tstamp>, which is what you should use too. It usually aliases |
50 | to the double type in C. |
50 | to the C<double> type in C, and when you need to do any calculations on |
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51 | it, you should treat it as such. |
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52 | |
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53 | |
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54 | =head1 GLOBAL FUNCTIONS |
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55 | |
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56 | These functions can be called anytime, even before initialising the |
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57 | library in any way. |
51 | |
58 | |
52 | =over 4 |
59 | =over 4 |
53 | |
60 | |
54 | =item ev_tstamp ev_time () |
61 | =item ev_tstamp ev_time () |
55 | |
62 | |
56 | Returns the current time as libev would use it. |
63 | Returns the current time as libev would use it. Please note that the |
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64 | C<ev_now> function is usually faster and also often returns the timestamp |
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65 | you actually want to know. |
57 | |
66 | |
58 | =item int ev_version_major () |
67 | =item int ev_version_major () |
59 | |
68 | |
60 | =item int ev_version_minor () |
69 | =item int ev_version_minor () |
61 | |
70 | |
… | |
… | |
63 | you linked against by calling the functions C<ev_version_major> and |
72 | you linked against by calling the functions C<ev_version_major> and |
64 | C<ev_version_minor>. If you want, you can compare against the global |
73 | C<ev_version_minor>. If you want, you can compare against the global |
65 | symbols C<EV_VERSION_MAJOR> and C<EV_VERSION_MINOR>, which specify the |
74 | symbols C<EV_VERSION_MAJOR> and C<EV_VERSION_MINOR>, which specify the |
66 | version of the library your program was compiled against. |
75 | version of the library your program was compiled against. |
67 | |
76 | |
68 | Usually, its a good idea to terminate if the major versions mismatch, |
77 | Usually, it's a good idea to terminate if the major versions mismatch, |
69 | as this indicates an incompatible change. Minor versions are usually |
78 | as this indicates an incompatible change. Minor versions are usually |
70 | compatible to older versions, so a larger minor version alone is usually |
79 | compatible to older versions, so a larger minor version alone is usually |
71 | not a problem. |
80 | not a problem. |
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81 | |
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82 | Example: make sure we haven't accidentally been linked against the wrong |
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83 | version: |
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84 | |
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85 | assert (("libev version mismatch", |
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86 | ev_version_major () == EV_VERSION_MAJOR |
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87 | && ev_version_minor () >= EV_VERSION_MINOR)); |
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88 | |
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89 | =item unsigned int ev_supported_backends () |
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90 | |
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91 | Return the set of all backends (i.e. their corresponding C<EV_BACKEND_*> |
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92 | value) compiled into this binary of libev (independent of their |
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93 | availability on the system you are running on). See C<ev_default_loop> for |
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94 | a description of the set values. |
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95 | |
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96 | Example: make sure we have the epoll method, because yeah this is cool and |
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97 | a must have and can we have a torrent of it please!!!11 |
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98 | |
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99 | assert (("sorry, no epoll, no sex", |
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100 | ev_supported_backends () & EVBACKEND_EPOLL)); |
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101 | |
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102 | =item unsigned int ev_recommended_backends () |
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103 | |
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104 | Return the set of all backends compiled into this binary of libev and also |
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105 | recommended for this platform. This set is often smaller than the one |
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106 | returned by C<ev_supported_backends>, as for example kqueue is broken on |
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107 | most BSDs and will not be autodetected unless you explicitly request it |
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108 | (assuming you know what you are doing). This is the set of backends that |
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109 | libev will probe for if you specify no backends explicitly. |
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110 | |
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111 | =item unsigned int ev_embeddable_backends () |
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112 | |
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113 | Returns the set of backends that are embeddable in other event loops. This |
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114 | is the theoretical, all-platform, value. To find which backends |
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115 | might be supported on the current system, you would need to look at |
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116 | C<ev_embeddable_backends () & ev_supported_backends ()>, likewise for |
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117 | recommended ones. |
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118 | |
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119 | See the description of C<ev_embed> watchers for more info. |
72 | |
120 | |
73 | =item ev_set_allocator (void *(*cb)(void *ptr, long size)) |
121 | =item ev_set_allocator (void *(*cb)(void *ptr, long size)) |
74 | |
122 | |
75 | Sets the allocation function to use (the prototype is similar to the |
123 | Sets the allocation function to use (the prototype is similar to the |
76 | realloc C function, the semantics are identical). It is used to allocate |
124 | realloc C function, the semantics are identical). It is used to allocate |
… | |
… | |
79 | destructive action. The default is your system realloc function. |
127 | destructive action. The default is your system realloc function. |
80 | |
128 | |
81 | You could override this function in high-availability programs to, say, |
129 | You could override this function in high-availability programs to, say, |
82 | free some memory if it cannot allocate memory, to use a special allocator, |
130 | free some memory if it cannot allocate memory, to use a special allocator, |
83 | or even to sleep a while and retry until some memory is available. |
131 | or even to sleep a while and retry until some memory is available. |
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132 | |
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133 | Example: replace the libev allocator with one that waits a bit and then |
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134 | retries: better than mine). |
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135 | |
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136 | static void * |
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137 | persistent_realloc (void *ptr, long size) |
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138 | { |
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139 | for (;;) |
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140 | { |
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141 | void *newptr = realloc (ptr, size); |
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142 | |
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143 | if (newptr) |
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144 | return newptr; |
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145 | |
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146 | sleep (60); |
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147 | } |
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148 | } |
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149 | |
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150 | ... |
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151 | ev_set_allocator (persistent_realloc); |
84 | |
152 | |
85 | =item ev_set_syserr_cb (void (*cb)(const char *msg)); |
153 | =item ev_set_syserr_cb (void (*cb)(const char *msg)); |
86 | |
154 | |
87 | Set the callback function to call on a retryable syscall error (such |
155 | Set the callback function to call on a retryable syscall error (such |
88 | as failed select, poll, epoll_wait). The message is a printable string |
156 | as failed select, poll, epoll_wait). The message is a printable string |
… | |
… | |
90 | callback is set, then libev will expect it to remedy the sitution, no |
158 | callback is set, then libev will expect it to remedy the sitution, no |
91 | matter what, when it returns. That is, libev will generally retry the |
159 | matter what, when it returns. That is, libev will generally retry the |
92 | requested operation, or, if the condition doesn't go away, do bad stuff |
160 | requested operation, or, if the condition doesn't go away, do bad stuff |
93 | (such as abort). |
161 | (such as abort). |
94 | |
162 | |
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163 | Example: do the same thing as libev does internally: |
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164 | |
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165 | static void |
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166 | fatal_error (const char *msg) |
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167 | { |
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168 | perror (msg); |
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169 | abort (); |
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170 | } |
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171 | |
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172 | ... |
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173 | ev_set_syserr_cb (fatal_error); |
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174 | |
95 | =back |
175 | =back |
96 | |
176 | |
97 | =head1 FUNCTIONS CONTROLLING THE EVENT LOOP |
177 | =head1 FUNCTIONS CONTROLLING THE EVENT LOOP |
98 | |
178 | |
99 | An event loop is described by a C<struct ev_loop *>. The library knows two |
179 | An event loop is described by a C<struct ev_loop *>. The library knows two |
100 | types of such loops, the I<default> loop, which supports signals and child |
180 | types of such loops, the I<default> loop, which supports signals and child |
101 | events, and dynamically created loops which do not. |
181 | events, and dynamically created loops which do not. |
102 | |
182 | |
103 | If you use threads, a common model is to run the default event loop |
183 | If you use threads, a common model is to run the default event loop |
104 | in your main thread (or in a separate thrad) and for each thread you |
184 | in your main thread (or in a separate thread) and for each thread you |
105 | create, you also create another event loop. Libev itself does no locking |
185 | create, you also create another event loop. Libev itself does no locking |
106 | whatsoever, so if you mix calls to the same event loop in different |
186 | whatsoever, so if you mix calls to the same event loop in different |
107 | threads, make sure you lock (this is usually a bad idea, though, even if |
187 | threads, make sure you lock (this is usually a bad idea, though, even if |
108 | done correctly, because its hideous and inefficient). |
188 | done correctly, because it's hideous and inefficient). |
109 | |
189 | |
110 | =over 4 |
190 | =over 4 |
111 | |
191 | |
112 | =item struct ev_loop *ev_default_loop (unsigned int flags) |
192 | =item struct ev_loop *ev_default_loop (unsigned int flags) |
113 | |
193 | |
114 | This will initialise the default event loop if it hasn't been initialised |
194 | This will initialise the default event loop if it hasn't been initialised |
115 | yet and return it. If the default loop could not be initialised, returns |
195 | yet and return it. If the default loop could not be initialised, returns |
116 | false. If it already was initialised it simply returns it (and ignores the |
196 | false. If it already was initialised it simply returns it (and ignores the |
117 | flags). |
197 | flags. If that is troubling you, check C<ev_backend ()> afterwards). |
118 | |
198 | |
119 | If you don't know what event loop to use, use the one returned from this |
199 | If you don't know what event loop to use, use the one returned from this |
120 | function. |
200 | function. |
121 | |
201 | |
122 | The flags argument can be used to specify special behaviour or specific |
202 | The flags argument can be used to specify special behaviour or specific |
123 | backends to use, and is usually specified as 0 (or EVFLAG_AUTO) |
203 | backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>). |
124 | |
204 | |
125 | It supports the following flags: |
205 | The following flags are supported: |
126 | |
206 | |
127 | =over 4 |
207 | =over 4 |
128 | |
208 | |
129 | =item EVFLAG_AUTO |
209 | =item C<EVFLAG_AUTO> |
130 | |
210 | |
131 | The default flags value. Use this if you have no clue (its the right |
211 | The default flags value. Use this if you have no clue (it's the right |
132 | thing, believe me). |
212 | thing, believe me). |
133 | |
213 | |
134 | =item EVFLAG_NOENV |
214 | =item C<EVFLAG_NOENV> |
135 | |
215 | |
136 | If this flag bit is ored into the flag value then libev will I<not> look |
216 | If this flag bit is ored into the flag value (or the program runs setuid |
137 | at the environment variable C<LIBEV_FLAGS>. Otherwise (the default), this |
217 | or setgid) then libev will I<not> look at the environment variable |
138 | environment variable will override the flags completely. This is useful |
218 | C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will |
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219 | override the flags completely if it is found in the environment. This is |
139 | to try out specific backends to tets their performance, or to work around |
220 | useful to try out specific backends to test their performance, or to work |
140 | bugs. |
221 | around bugs. |
141 | |
222 | |
142 | =item EVMETHOD_SELECT portable select backend |
223 | =item C<EVBACKEND_SELECT> (value 1, portable select backend) |
143 | |
224 | |
144 | =item EVMETHOD_POLL poll backend (everywhere except windows) |
225 | This is your standard select(2) backend. Not I<completely> standard, as |
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226 | libev tries to roll its own fd_set with no limits on the number of fds, |
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227 | but if that fails, expect a fairly low limit on the number of fds when |
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228 | using this backend. It doesn't scale too well (O(highest_fd)), but its usually |
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229 | the fastest backend for a low number of fds. |
145 | |
230 | |
146 | =item EVMETHOD_EPOLL linux only |
231 | =item C<EVBACKEND_POLL> (value 2, poll backend, available everywhere except on windows) |
147 | |
232 | |
148 | =item EVMETHOD_KQUEUE some bsds only |
233 | And this is your standard poll(2) backend. It's more complicated than |
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234 | select, but handles sparse fds better and has no artificial limit on the |
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235 | number of fds you can use (except it will slow down considerably with a |
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236 | lot of inactive fds). It scales similarly to select, i.e. O(total_fds). |
149 | |
237 | |
150 | =item EVMETHOD_DEVPOLL solaris 8 only |
238 | =item C<EVBACKEND_EPOLL> (value 4, Linux) |
151 | |
239 | |
152 | =item EVMETHOD_PORT solaris 10 only |
240 | For few fds, this backend is a bit little slower than poll and select, |
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241 | but it scales phenomenally better. While poll and select usually scale like |
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242 | O(total_fds) where n is the total number of fds (or the highest fd), epoll scales |
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243 | either O(1) or O(active_fds). |
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244 | |
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245 | While stopping and starting an I/O watcher in the same iteration will |
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246 | result in some caching, there is still a syscall per such incident |
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247 | (because the fd could point to a different file description now), so its |
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248 | best to avoid that. Also, dup()ed file descriptors might not work very |
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249 | well if you register events for both fds. |
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250 | |
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251 | Please note that epoll sometimes generates spurious notifications, so you |
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252 | need to use non-blocking I/O or other means to avoid blocking when no data |
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253 | (or space) is available. |
|
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254 | |
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255 | =item C<EVBACKEND_KQUEUE> (value 8, most BSD clones) |
|
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256 | |
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257 | Kqueue deserves special mention, as at the time of this writing, it |
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258 | was broken on all BSDs except NetBSD (usually it doesn't work with |
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259 | anything but sockets and pipes, except on Darwin, where of course its |
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260 | completely useless). For this reason its not being "autodetected" |
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261 | unless you explicitly specify it explicitly in the flags (i.e. using |
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262 | C<EVBACKEND_KQUEUE>). |
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263 | |
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264 | It scales in the same way as the epoll backend, but the interface to the |
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265 | kernel is more efficient (which says nothing about its actual speed, of |
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266 | course). While starting and stopping an I/O watcher does not cause an |
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267 | extra syscall as with epoll, it still adds up to four event changes per |
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268 | incident, so its best to avoid that. |
|
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269 | |
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270 | =item C<EVBACKEND_DEVPOLL> (value 16, Solaris 8) |
|
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271 | |
|
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272 | This is not implemented yet (and might never be). |
|
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273 | |
|
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274 | =item C<EVBACKEND_PORT> (value 32, Solaris 10) |
|
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275 | |
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276 | This uses the Solaris 10 port mechanism. As with everything on Solaris, |
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277 | it's really slow, but it still scales very well (O(active_fds)). |
|
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278 | |
|
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279 | Please note that solaris ports can result in a lot of spurious |
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280 | notifications, so you need to use non-blocking I/O or other means to avoid |
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281 | blocking when no data (or space) is available. |
|
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282 | |
|
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283 | =item C<EVBACKEND_ALL> |
|
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284 | |
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285 | Try all backends (even potentially broken ones that wouldn't be tried |
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286 | with C<EVFLAG_AUTO>). Since this is a mask, you can do stuff such as |
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287 | C<EVBACKEND_ALL & ~EVBACKEND_KQUEUE>. |
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288 | |
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289 | =back |
153 | |
290 | |
154 | If one or more of these are ored into the flags value, then only these |
291 | If one or more of these are ored into the flags value, then only these |
155 | backends will be tried (in the reverse order as given here). If one are |
292 | backends will be tried (in the reverse order as given here). If none are |
156 | specified, any backend will do. |
293 | specified, most compiled-in backend will be tried, usually in reverse |
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294 | order of their flag values :) |
157 | |
295 | |
158 | =back |
296 | The most typical usage is like this: |
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297 | |
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298 | if (!ev_default_loop (0)) |
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299 | fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?"); |
|
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300 | |
|
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301 | Restrict libev to the select and poll backends, and do not allow |
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302 | environment settings to be taken into account: |
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303 | |
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304 | ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV); |
|
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305 | |
|
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306 | Use whatever libev has to offer, but make sure that kqueue is used if |
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307 | available (warning, breaks stuff, best use only with your own private |
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308 | event loop and only if you know the OS supports your types of fds): |
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309 | |
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310 | ev_default_loop (ev_recommended_backends () | EVBACKEND_KQUEUE); |
159 | |
311 | |
160 | =item struct ev_loop *ev_loop_new (unsigned int flags) |
312 | =item struct ev_loop *ev_loop_new (unsigned int flags) |
161 | |
313 | |
162 | Similar to C<ev_default_loop>, but always creates a new event loop that is |
314 | Similar to C<ev_default_loop>, but always creates a new event loop that is |
163 | always distinct from the default loop. Unlike the default loop, it cannot |
315 | always distinct from the default loop. Unlike the default loop, it cannot |
164 | handle signal and child watchers, and attempts to do so will be greeted by |
316 | handle signal and child watchers, and attempts to do so will be greeted by |
165 | undefined behaviour (or a failed assertion if assertions are enabled). |
317 | undefined behaviour (or a failed assertion if assertions are enabled). |
166 | |
318 | |
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319 | Example: try to create a event loop that uses epoll and nothing else. |
|
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320 | |
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321 | struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
|
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322 | if (!epoller) |
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323 | fatal ("no epoll found here, maybe it hides under your chair"); |
|
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324 | |
167 | =item ev_default_destroy () |
325 | =item ev_default_destroy () |
168 | |
326 | |
169 | Destroys the default loop again (frees all memory and kernel state |
327 | Destroys the default loop again (frees all memory and kernel state |
170 | etc.). This stops all registered event watchers (by not touching them in |
328 | etc.). This stops all registered event watchers (by not touching them in |
171 | any way whatsoever, although you cnanot rely on this :). |
329 | any way whatsoever, although you cannot rely on this :). |
172 | |
330 | |
173 | =item ev_loop_destroy (loop) |
331 | =item ev_loop_destroy (loop) |
174 | |
332 | |
175 | Like C<ev_default_destroy>, but destroys an event loop created by an |
333 | Like C<ev_default_destroy>, but destroys an event loop created by an |
176 | earlier call to C<ev_loop_new>. |
334 | earlier call to C<ev_loop_new>. |
… | |
… | |
180 | This function reinitialises the kernel state for backends that have |
338 | This function reinitialises the kernel state for backends that have |
181 | one. Despite the name, you can call it anytime, but it makes most sense |
339 | one. Despite the name, you can call it anytime, but it makes most sense |
182 | after forking, in either the parent or child process (or both, but that |
340 | after forking, in either the parent or child process (or both, but that |
183 | again makes little sense). |
341 | again makes little sense). |
184 | |
342 | |
185 | You I<must> call this function after forking if and only if you want to |
343 | You I<must> call this function in the child process after forking if and |
186 | use the event library in both processes. If you just fork+exec, you don't |
344 | only if you want to use the event library in both processes. If you just |
187 | have to call it. |
345 | fork+exec, you don't have to call it. |
188 | |
346 | |
189 | The function itself is quite fast and its usually not a problem to call |
347 | The function itself is quite fast and it's usually not a problem to call |
190 | it just in case after a fork. To make this easy, the function will fit in |
348 | it just in case after a fork. To make this easy, the function will fit in |
191 | quite nicely into a call to C<pthread_atfork>: |
349 | quite nicely into a call to C<pthread_atfork>: |
192 | |
350 | |
193 | pthread_atfork (0, 0, ev_default_fork); |
351 | pthread_atfork (0, 0, ev_default_fork); |
|
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352 | |
|
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353 | At the moment, C<EVBACKEND_SELECT> and C<EVBACKEND_POLL> are safe to use |
|
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354 | without calling this function, so if you force one of those backends you |
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355 | do not need to care. |
194 | |
356 | |
195 | =item ev_loop_fork (loop) |
357 | =item ev_loop_fork (loop) |
196 | |
358 | |
197 | Like C<ev_default_fork>, but acts on an event loop created by |
359 | Like C<ev_default_fork>, but acts on an event loop created by |
198 | C<ev_loop_new>. Yes, you have to call this on every allocated event loop |
360 | C<ev_loop_new>. Yes, you have to call this on every allocated event loop |
199 | after fork, and how you do this is entirely your own problem. |
361 | after fork, and how you do this is entirely your own problem. |
200 | |
362 | |
201 | =item unsigned int ev_method (loop) |
363 | =item unsigned int ev_backend (loop) |
202 | |
364 | |
203 | Returns one of the C<EVMETHOD_*> flags indicating the event backend in |
365 | Returns one of the C<EVBACKEND_*> flags indicating the event backend in |
204 | use. |
366 | use. |
205 | |
367 | |
206 | =item ev_tstamp = ev_now (loop) |
368 | =item ev_tstamp ev_now (loop) |
207 | |
369 | |
208 | Returns the current "event loop time", which is the time the event loop |
370 | Returns the current "event loop time", which is the time the event loop |
209 | got events and started processing them. This timestamp does not change |
371 | received events and started processing them. This timestamp does not |
210 | as long as callbacks are being processed, and this is also the base time |
372 | change as long as callbacks are being processed, and this is also the base |
211 | used for relative timers. You can treat it as the timestamp of the event |
373 | time used for relative timers. You can treat it as the timestamp of the |
212 | occuring (or more correctly, the mainloop finding out about it). |
374 | event occuring (or more correctly, libev finding out about it). |
213 | |
375 | |
214 | =item ev_loop (loop, int flags) |
376 | =item ev_loop (loop, int flags) |
215 | |
377 | |
216 | Finally, this is it, the event handler. This function usually is called |
378 | Finally, this is it, the event handler. This function usually is called |
217 | after you initialised all your watchers and you want to start handling |
379 | after you initialised all your watchers and you want to start handling |
218 | events. |
380 | events. |
219 | |
381 | |
220 | If the flags argument is specified as 0, it will not return until either |
382 | If the flags argument is specified as C<0>, it will not return until |
221 | no event watchers are active anymore or C<ev_unloop> was called. |
383 | either no event watchers are active anymore or C<ev_unloop> was called. |
|
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384 | |
|
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385 | Please note that an explicit C<ev_unloop> is usually better than |
|
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386 | relying on all watchers to be stopped when deciding when a program has |
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387 | finished (especially in interactive programs), but having a program that |
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388 | automatically loops as long as it has to and no longer by virtue of |
|
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389 | relying on its watchers stopping correctly is a thing of beauty. |
222 | |
390 | |
223 | A flags value of C<EVLOOP_NONBLOCK> will look for new events, will handle |
391 | A flags value of C<EVLOOP_NONBLOCK> will look for new events, will handle |
224 | those events and any outstanding ones, but will not block your process in |
392 | those events and any outstanding ones, but will not block your process in |
225 | case there are no events. |
393 | case there are no events and will return after one iteration of the loop. |
226 | |
394 | |
227 | A flags value of C<EVLOOP_ONESHOT> will look for new events (waiting if |
395 | A flags value of C<EVLOOP_ONESHOT> will look for new events (waiting if |
228 | neccessary) and will handle those and any outstanding ones. It will block |
396 | neccessary) and will handle those and any outstanding ones. It will block |
229 | your process until at least one new event arrives. |
397 | your process until at least one new event arrives, and will return after |
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398 | one iteration of the loop. This is useful if you are waiting for some |
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399 | external event in conjunction with something not expressible using other |
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400 | libev watchers. However, a pair of C<ev_prepare>/C<ev_check> watchers is |
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401 | usually a better approach for this kind of thing. |
230 | |
402 | |
231 | This flags value could be used to implement alternative looping |
403 | Here are the gory details of what C<ev_loop> does: |
232 | constructs, but the C<prepare> and C<check> watchers provide a better and |
404 | |
233 | more generic mechanism. |
405 | * If there are no active watchers (reference count is zero), return. |
|
|
406 | - Queue prepare watchers and then call all outstanding watchers. |
|
|
407 | - If we have been forked, recreate the kernel state. |
|
|
408 | - Update the kernel state with all outstanding changes. |
|
|
409 | - Update the "event loop time". |
|
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410 | - Calculate for how long to block. |
|
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411 | - Block the process, waiting for any events. |
|
|
412 | - Queue all outstanding I/O (fd) events. |
|
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413 | - Update the "event loop time" and do time jump handling. |
|
|
414 | - Queue all outstanding timers. |
|
|
415 | - Queue all outstanding periodics. |
|
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416 | - If no events are pending now, queue all idle watchers. |
|
|
417 | - Queue all check watchers. |
|
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418 | - Call all queued watchers in reverse order (i.e. check watchers first). |
|
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419 | Signals and child watchers are implemented as I/O watchers, and will |
|
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420 | be handled here by queueing them when their watcher gets executed. |
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421 | - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
|
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422 | were used, return, otherwise continue with step *. |
|
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423 | |
|
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424 | Example: queue some jobs and then loop until no events are outsanding |
|
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425 | anymore. |
|
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426 | |
|
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427 | ... queue jobs here, make sure they register event watchers as long |
|
|
428 | ... as they still have work to do (even an idle watcher will do..) |
|
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429 | ev_loop (my_loop, 0); |
|
|
430 | ... jobs done. yeah! |
234 | |
431 | |
235 | =item ev_unloop (loop, how) |
432 | =item ev_unloop (loop, how) |
236 | |
433 | |
237 | Can be used to make a call to C<ev_loop> return early. The C<how> argument |
434 | Can be used to make a call to C<ev_loop> return early (but only after it |
|
|
435 | has processed all outstanding events). The C<how> argument must be either |
238 | must be either C<EVUNLOOP_ONCE>, which will make the innermost C<ev_loop> |
436 | C<EVUNLOOP_ONE>, which will make the innermost C<ev_loop> call return, or |
239 | call return, or C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> |
437 | C<EVUNLOOP_ALL>, which will make all nested C<ev_loop> calls return. |
240 | calls return. |
|
|
241 | |
438 | |
242 | =item ev_ref (loop) |
439 | =item ev_ref (loop) |
243 | |
440 | |
244 | =item ev_unref (loop) |
441 | =item ev_unref (loop) |
245 | |
442 | |
246 | Ref/unref can be used to add or remove a refcount on the event loop: Every |
443 | Ref/unref can be used to add or remove a reference count on the event |
247 | watcher keeps one reference. If you have a long-runing watcher you never |
444 | loop: Every watcher keeps one reference, and as long as the reference |
248 | unregister that should not keep ev_loop from running, ev_unref() after |
445 | count is nonzero, C<ev_loop> will not return on its own. If you have |
249 | starting, and ev_ref() before stopping it. Libev itself uses this for |
446 | a watcher you never unregister that should not keep C<ev_loop> from |
250 | example for its internal signal pipe: It is not visible to you as a user |
447 | returning, ev_unref() after starting, and ev_ref() before stopping it. For |
251 | and should not keep C<ev_loop> from exiting if the work is done. It is |
448 | example, libev itself uses this for its internal signal pipe: It is not |
252 | also an excellent way to do this for generic recurring timers or from |
449 | visible to the libev user and should not keep C<ev_loop> from exiting if |
253 | within third-party libraries. Just remember to unref after start and ref |
450 | no event watchers registered by it are active. It is also an excellent |
254 | before stop. |
451 | way to do this for generic recurring timers or from within third-party |
|
|
452 | libraries. Just remember to I<unref after start> and I<ref before stop>. |
|
|
453 | |
|
|
454 | Example: create a signal watcher, but keep it from keeping C<ev_loop> |
|
|
455 | running when nothing else is active. |
|
|
456 | |
|
|
457 | struct dv_signal exitsig; |
|
|
458 | ev_signal_init (&exitsig, sig_cb, SIGINT); |
|
|
459 | ev_signal_start (myloop, &exitsig); |
|
|
460 | evf_unref (myloop); |
|
|
461 | |
|
|
462 | Example: for some weird reason, unregister the above signal handler again. |
|
|
463 | |
|
|
464 | ev_ref (myloop); |
|
|
465 | ev_signal_stop (myloop, &exitsig); |
255 | |
466 | |
256 | =back |
467 | =back |
257 | |
468 | |
258 | =head1 ANATOMY OF A WATCHER |
469 | =head1 ANATOMY OF A WATCHER |
259 | |
470 | |
260 | A watcher is a structure that you create and register to record your |
471 | A watcher is a structure that you create and register to record your |
261 | interest in some event. For instance, if you want to wait for STDIN to |
472 | interest in some event. For instance, if you want to wait for STDIN to |
262 | become readable, you would create an ev_io watcher for that: |
473 | become readable, you would create an C<ev_io> watcher for that: |
263 | |
474 | |
264 | static void my_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
475 | static void my_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
265 | { |
476 | { |
266 | ev_io_stop (w); |
477 | ev_io_stop (w); |
267 | ev_unloop (loop, EVUNLOOP_ALL); |
478 | ev_unloop (loop, EVUNLOOP_ALL); |
… | |
… | |
294 | *) >>), and you can stop watching for events at any time by calling the |
505 | *) >>), and you can stop watching for events at any time by calling the |
295 | corresponding stop function (C<< ev_<type>_stop (loop, watcher *) >>. |
506 | corresponding stop function (C<< ev_<type>_stop (loop, watcher *) >>. |
296 | |
507 | |
297 | As long as your watcher is active (has been started but not stopped) you |
508 | As long as your watcher is active (has been started but not stopped) you |
298 | must not touch the values stored in it. Most specifically you must never |
509 | must not touch the values stored in it. Most specifically you must never |
299 | reinitialise it or call its set method. |
510 | reinitialise it or call its set macro. |
300 | |
511 | |
301 | You cna check whether an event is active by calling the C<ev_is_active |
512 | You can check whether an event is active by calling the C<ev_is_active |
302 | (watcher *)> macro. To see whether an event is outstanding (but the |
513 | (watcher *)> macro. To see whether an event is outstanding (but the |
303 | callback for it has not been called yet) you cna use the C<ev_is_pending |
514 | callback for it has not been called yet) you can use the C<ev_is_pending |
304 | (watcher *)> macro. |
515 | (watcher *)> macro. |
305 | |
516 | |
306 | Each and every callback receives the event loop pointer as first, the |
517 | Each and every callback receives the event loop pointer as first, the |
307 | registered watcher structure as second, and a bitset of received events as |
518 | registered watcher structure as second, and a bitset of received events as |
308 | third argument. |
519 | third argument. |
309 | |
520 | |
310 | The rceeived events usually include a single bit per event type received |
521 | The received events usually include a single bit per event type received |
311 | (you can receive multiple events at the same time). The possible bit masks |
522 | (you can receive multiple events at the same time). The possible bit masks |
312 | are: |
523 | are: |
313 | |
524 | |
314 | =over 4 |
525 | =over 4 |
315 | |
526 | |
316 | =item EV_READ |
527 | =item C<EV_READ> |
317 | |
528 | |
318 | =item EV_WRITE |
529 | =item C<EV_WRITE> |
319 | |
530 | |
320 | The file descriptor in the ev_io watcher has become readable and/or |
531 | The file descriptor in the C<ev_io> watcher has become readable and/or |
321 | writable. |
532 | writable. |
322 | |
533 | |
323 | =item EV_TIMEOUT |
534 | =item C<EV_TIMEOUT> |
324 | |
535 | |
325 | The ev_timer watcher has timed out. |
536 | The C<ev_timer> watcher has timed out. |
326 | |
537 | |
327 | =item EV_PERIODIC |
538 | =item C<EV_PERIODIC> |
328 | |
539 | |
329 | The ev_periodic watcher has timed out. |
540 | The C<ev_periodic> watcher has timed out. |
330 | |
541 | |
331 | =item EV_SIGNAL |
542 | =item C<EV_SIGNAL> |
332 | |
543 | |
333 | The signal specified in the ev_signal watcher has been received by a thread. |
544 | The signal specified in the C<ev_signal> watcher has been received by a thread. |
334 | |
545 | |
335 | =item EV_CHILD |
546 | =item C<EV_CHILD> |
336 | |
547 | |
337 | The pid specified in the ev_child watcher has received a status change. |
548 | The pid specified in the C<ev_child> watcher has received a status change. |
338 | |
549 | |
339 | =item EV_IDLE |
550 | =item C<EV_IDLE> |
340 | |
551 | |
341 | The ev_idle watcher has determined that you have nothing better to do. |
552 | The C<ev_idle> watcher has determined that you have nothing better to do. |
342 | |
553 | |
343 | =item EV_PREPARE |
554 | =item C<EV_PREPARE> |
344 | |
555 | |
345 | =item EV_CHECK |
556 | =item C<EV_CHECK> |
346 | |
557 | |
347 | All ev_prepare watchers are invoked just I<before> C<ev_loop> starts |
558 | All C<ev_prepare> watchers are invoked just I<before> C<ev_loop> starts |
348 | to gather new events, and all ev_check watchers are invoked just after |
559 | to gather new events, and all C<ev_check> watchers are invoked just after |
349 | C<ev_loop> has gathered them, but before it invokes any callbacks for any |
560 | C<ev_loop> has gathered them, but before it invokes any callbacks for any |
350 | received events. Callbacks of both watcher types can start and stop as |
561 | received events. Callbacks of both watcher types can start and stop as |
351 | many watchers as they want, and all of them will be taken into account |
562 | many watchers as they want, and all of them will be taken into account |
352 | (for example, a ev_prepare watcher might start an idle watcher to keep |
563 | (for example, a C<ev_prepare> watcher might start an idle watcher to keep |
353 | C<ev_loop> from blocking). |
564 | C<ev_loop> from blocking). |
354 | |
565 | |
355 | =item EV_ERROR |
566 | =item C<EV_ERROR> |
356 | |
567 | |
357 | An unspecified error has occured, the watcher has been stopped. This might |
568 | An unspecified error has occured, the watcher has been stopped. This might |
358 | happen because the watcher could not be properly started because libev |
569 | happen because the watcher could not be properly started because libev |
359 | ran out of memory, a file descriptor was found to be closed or any other |
570 | ran out of memory, a file descriptor was found to be closed or any other |
360 | problem. You best act on it by reporting the problem and somehow coping |
571 | problem. You best act on it by reporting the problem and somehow coping |
… | |
… | |
369 | =back |
580 | =back |
370 | |
581 | |
371 | =head2 ASSOCIATING CUSTOM DATA WITH A WATCHER |
582 | =head2 ASSOCIATING CUSTOM DATA WITH A WATCHER |
372 | |
583 | |
373 | Each watcher has, by default, a member C<void *data> that you can change |
584 | Each watcher has, by default, a member C<void *data> that you can change |
374 | and read at any time, libev will completely ignore it. This cna be used |
585 | and read at any time, libev will completely ignore it. This can be used |
375 | to associate arbitrary data with your watcher. If you need more data and |
586 | to associate arbitrary data with your watcher. If you need more data and |
376 | don't want to allocate memory and store a pointer to it in that data |
587 | don't want to allocate memory and store a pointer to it in that data |
377 | member, you can also "subclass" the watcher type and provide your own |
588 | member, you can also "subclass" the watcher type and provide your own |
378 | data: |
589 | data: |
379 | |
590 | |
… | |
… | |
401 | =head1 WATCHER TYPES |
612 | =head1 WATCHER TYPES |
402 | |
613 | |
403 | This section describes each watcher in detail, but will not repeat |
614 | This section describes each watcher in detail, but will not repeat |
404 | information given in the last section. |
615 | information given in the last section. |
405 | |
616 | |
|
|
617 | |
406 | =head2 struct ev_io - is my file descriptor readable or writable |
618 | =head2 C<ev_io> - is this file descriptor readable or writable |
407 | |
619 | |
408 | I/O watchers check whether a file descriptor is readable or writable |
620 | I/O watchers check whether a file descriptor is readable or writable |
409 | in each iteration of the event loop (This behaviour is called |
621 | in each iteration of the event loop (This behaviour is called |
410 | level-triggering because you keep receiving events as long as the |
622 | level-triggering because you keep receiving events as long as the |
411 | condition persists. Remember you cna stop the watcher if you don't want to |
623 | condition persists. Remember you can stop the watcher if you don't want to |
412 | act on the event and neither want to receive future events). |
624 | act on the event and neither want to receive future events). |
413 | |
625 | |
|
|
626 | In general you can register as many read and/or write event watchers per |
|
|
627 | fd as you want (as long as you don't confuse yourself). Setting all file |
|
|
628 | descriptors to non-blocking mode is also usually a good idea (but not |
|
|
629 | required if you know what you are doing). |
|
|
630 | |
|
|
631 | You have to be careful with dup'ed file descriptors, though. Some backends |
|
|
632 | (the linux epoll backend is a notable example) cannot handle dup'ed file |
|
|
633 | descriptors correctly if you register interest in two or more fds pointing |
|
|
634 | to the same underlying file/socket etc. description (that is, they share |
|
|
635 | the same underlying "file open"). |
|
|
636 | |
|
|
637 | If you must do this, then force the use of a known-to-be-good backend |
|
|
638 | (at the time of this writing, this includes only C<EVBACKEND_SELECT> and |
|
|
639 | C<EVBACKEND_POLL>). |
|
|
640 | |
414 | =over 4 |
641 | =over 4 |
415 | |
642 | |
416 | =item ev_io_init (ev_io *, callback, int fd, int events) |
643 | =item ev_io_init (ev_io *, callback, int fd, int events) |
417 | |
644 | |
418 | =item ev_io_set (ev_io *, int fd, int events) |
645 | =item ev_io_set (ev_io *, int fd, int events) |
419 | |
646 | |
420 | Configures an ev_io watcher. The fd is the file descriptor to rceeive |
647 | Configures an C<ev_io> watcher. The fd is the file descriptor to rceeive |
421 | events for and events is either C<EV_READ>, C<EV_WRITE> or C<EV_READ | |
648 | events for and events is either C<EV_READ>, C<EV_WRITE> or C<EV_READ | |
422 | EV_WRITE> to receive the given events. |
649 | EV_WRITE> to receive the given events. |
423 | |
650 | |
424 | =back |
651 | Please note that most of the more scalable backend mechanisms (for example |
|
|
652 | epoll and solaris ports) can result in spurious readyness notifications |
|
|
653 | for file descriptors, so you practically need to use non-blocking I/O (and |
|
|
654 | treat callback invocation as hint only), or retest separately with a safe |
|
|
655 | interface before doing I/O (XLib can do this), or force the use of either |
|
|
656 | C<EVBACKEND_SELECT> or C<EVBACKEND_POLL>, which don't suffer from this |
|
|
657 | problem. Also note that it is quite easy to have your callback invoked |
|
|
658 | when the readyness condition is no longer valid even when employing |
|
|
659 | typical ways of handling events, so its a good idea to use non-blocking |
|
|
660 | I/O unconditionally. |
425 | |
661 | |
|
|
662 | =back |
|
|
663 | |
|
|
664 | Example: call C<stdin_readable_cb> when STDIN_FILENO has become, well |
|
|
665 | readable, but only once. Since it is likely line-buffered, you could |
|
|
666 | attempt to read a whole line in the callback: |
|
|
667 | |
|
|
668 | static void |
|
|
669 | stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
|
|
670 | { |
|
|
671 | ev_io_stop (loop, w); |
|
|
672 | .. read from stdin here (or from w->fd) and haqndle any I/O errors |
|
|
673 | } |
|
|
674 | |
|
|
675 | ... |
|
|
676 | struct ev_loop *loop = ev_default_init (0); |
|
|
677 | struct ev_io stdin_readable; |
|
|
678 | ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ); |
|
|
679 | ev_io_start (loop, &stdin_readable); |
|
|
680 | ev_loop (loop, 0); |
|
|
681 | |
|
|
682 | |
426 | =head2 struct ev_timer - relative and optionally recurring timeouts |
683 | =head2 C<ev_timer> - relative and optionally recurring timeouts |
427 | |
684 | |
428 | Timer watchers are simple relative timers that generate an event after a |
685 | Timer watchers are simple relative timers that generate an event after a |
429 | given time, and optionally repeating in regular intervals after that. |
686 | given time, and optionally repeating in regular intervals after that. |
430 | |
687 | |
431 | The timers are based on real time, that is, if you register an event that |
688 | The timers are based on real time, that is, if you register an event that |
432 | times out after an hour and youreset your system clock to last years |
689 | times out after an hour and you reset your system clock to last years |
433 | time, it will still time out after (roughly) and hour. "Roughly" because |
690 | time, it will still time out after (roughly) and hour. "Roughly" because |
434 | detecting time jumps is hard, and soem inaccuracies are unavoidable (the |
691 | detecting time jumps is hard, and some inaccuracies are unavoidable (the |
435 | monotonic clock option helps a lot here). |
692 | monotonic clock option helps a lot here). |
|
|
693 | |
|
|
694 | The relative timeouts are calculated relative to the C<ev_now ()> |
|
|
695 | time. This is usually the right thing as this timestamp refers to the time |
|
|
696 | of the event triggering whatever timeout you are modifying/starting. If |
|
|
697 | you suspect event processing to be delayed and you I<need> to base the timeout |
|
|
698 | on the current time, use something like this to adjust for this: |
|
|
699 | |
|
|
700 | ev_timer_set (&timer, after + ev_now () - ev_time (), 0.); |
|
|
701 | |
|
|
702 | The callback is guarenteed to be invoked only when its timeout has passed, |
|
|
703 | but if multiple timers become ready during the same loop iteration then |
|
|
704 | order of execution is undefined. |
436 | |
705 | |
437 | =over 4 |
706 | =over 4 |
438 | |
707 | |
439 | =item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat) |
708 | =item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat) |
440 | |
709 | |
… | |
… | |
446 | later, again, and again, until stopped manually. |
715 | later, again, and again, until stopped manually. |
447 | |
716 | |
448 | The timer itself will do a best-effort at avoiding drift, that is, if you |
717 | The timer itself will do a best-effort at avoiding drift, that is, if you |
449 | configure a timer to trigger every 10 seconds, then it will trigger at |
718 | configure a timer to trigger every 10 seconds, then it will trigger at |
450 | exactly 10 second intervals. If, however, your program cannot keep up with |
719 | exactly 10 second intervals. If, however, your program cannot keep up with |
451 | the timer (ecause it takes longer than those 10 seconds to do stuff) the |
720 | the timer (because it takes longer than those 10 seconds to do stuff) the |
452 | timer will not fire more than once per event loop iteration. |
721 | timer will not fire more than once per event loop iteration. |
453 | |
722 | |
454 | =item ev_timer_again (loop) |
723 | =item ev_timer_again (loop) |
455 | |
724 | |
456 | This will act as if the timer timed out and restart it again if it is |
725 | This will act as if the timer timed out and restart it again if it is |
… | |
… | |
463 | |
732 | |
464 | This sounds a bit complicated, but here is a useful and typical |
733 | This sounds a bit complicated, but here is a useful and typical |
465 | example: Imagine you have a tcp connection and you want a so-called idle |
734 | example: Imagine you have a tcp connection and you want a so-called idle |
466 | timeout, that is, you want to be called when there have been, say, 60 |
735 | timeout, that is, you want to be called when there have been, say, 60 |
467 | seconds of inactivity on the socket. The easiest way to do this is to |
736 | seconds of inactivity on the socket. The easiest way to do this is to |
468 | configure an ev_timer with after=repeat=60 and calling ev_timer_again each |
737 | configure an C<ev_timer> with after=repeat=60 and calling ev_timer_again each |
469 | time you successfully read or write some data. If you go into an idle |
738 | time you successfully read or write some data. If you go into an idle |
470 | state where you do not expect data to travel on the socket, you can stop |
739 | state where you do not expect data to travel on the socket, you can stop |
471 | the timer, and again will automatically restart it if need be. |
740 | the timer, and again will automatically restart it if need be. |
472 | |
741 | |
473 | =back |
742 | =back |
474 | |
743 | |
|
|
744 | Example: create a timer that fires after 60 seconds. |
|
|
745 | |
|
|
746 | static void |
|
|
747 | one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
|
|
748 | { |
|
|
749 | .. one minute over, w is actually stopped right here |
|
|
750 | } |
|
|
751 | |
|
|
752 | struct ev_timer mytimer; |
|
|
753 | ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
|
|
754 | ev_timer_start (loop, &mytimer); |
|
|
755 | |
|
|
756 | Example: create a timeout timer that times out after 10 seconds of |
|
|
757 | inactivity. |
|
|
758 | |
|
|
759 | static void |
|
|
760 | timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
|
|
761 | { |
|
|
762 | .. ten seconds without any activity |
|
|
763 | } |
|
|
764 | |
|
|
765 | struct ev_timer mytimer; |
|
|
766 | ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */ |
|
|
767 | ev_timer_again (&mytimer); /* start timer */ |
|
|
768 | ev_loop (loop, 0); |
|
|
769 | |
|
|
770 | // and in some piece of code that gets executed on any "activity": |
|
|
771 | // reset the timeout to start ticking again at 10 seconds |
|
|
772 | ev_timer_again (&mytimer); |
|
|
773 | |
|
|
774 | |
475 | =head2 ev_periodic - to cron or not to cron it |
775 | =head2 C<ev_periodic> - to cron or not to cron |
476 | |
776 | |
477 | Periodic watchers are also timers of a kind, but they are very versatile |
777 | Periodic watchers are also timers of a kind, but they are very versatile |
478 | (and unfortunately a bit complex). |
778 | (and unfortunately a bit complex). |
479 | |
779 | |
480 | Unlike ev_timer's, they are not based on real time (or relative time) |
780 | Unlike C<ev_timer>'s, they are not based on real time (or relative time) |
481 | but on wallclock time (absolute time). You can tell a periodic watcher |
781 | but on wallclock time (absolute time). You can tell a periodic watcher |
482 | to trigger "at" some specific point in time. For example, if you tell a |
782 | to trigger "at" some specific point in time. For example, if you tell a |
483 | periodic watcher to trigger in 10 seconds (by specifiying e.g. c<ev_now () |
783 | periodic watcher to trigger in 10 seconds (by specifiying e.g. c<ev_now () |
484 | + 10.>) and then reset your system clock to the last year, then it will |
784 | + 10.>) and then reset your system clock to the last year, then it will |
485 | take a year to trigger the event (unlike an ev_timer, which would trigger |
785 | take a year to trigger the event (unlike an C<ev_timer>, which would trigger |
486 | roughly 10 seconds later and of course not if you reset your system time |
786 | roughly 10 seconds later and of course not if you reset your system time |
487 | again). |
787 | again). |
488 | |
788 | |
489 | They can also be used to implement vastly more complex timers, such as |
789 | They can also be used to implement vastly more complex timers, such as |
490 | triggering an event on eahc midnight, local time. |
790 | triggering an event on eahc midnight, local time. |
491 | |
791 | |
|
|
792 | As with timers, the callback is guarenteed to be invoked only when the |
|
|
793 | time (C<at>) has been passed, but if multiple periodic timers become ready |
|
|
794 | during the same loop iteration then order of execution is undefined. |
|
|
795 | |
492 | =over 4 |
796 | =over 4 |
493 | |
797 | |
494 | =item ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb) |
798 | =item ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb) |
495 | |
799 | |
496 | =item ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb) |
800 | =item ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb) |
497 | |
801 | |
498 | Lots of arguments, lets sort it out... There are basically three modes of |
802 | Lots of arguments, lets sort it out... There are basically three modes of |
499 | operation, and we will explain them from simplest to complex: |
803 | operation, and we will explain them from simplest to complex: |
500 | |
|
|
501 | |
804 | |
502 | =over 4 |
805 | =over 4 |
503 | |
806 | |
504 | =item * absolute timer (interval = reschedule_cb = 0) |
807 | =item * absolute timer (interval = reschedule_cb = 0) |
505 | |
808 | |
… | |
… | |
519 | |
822 | |
520 | ev_periodic_set (&periodic, 0., 3600., 0); |
823 | ev_periodic_set (&periodic, 0., 3600., 0); |
521 | |
824 | |
522 | This doesn't mean there will always be 3600 seconds in between triggers, |
825 | This doesn't mean there will always be 3600 seconds in between triggers, |
523 | but only that the the callback will be called when the system time shows a |
826 | but only that the the callback will be called when the system time shows a |
524 | full hour (UTC), or more correct, when the system time is evenly divisible |
827 | full hour (UTC), or more correctly, when the system time is evenly divisible |
525 | by 3600. |
828 | by 3600. |
526 | |
829 | |
527 | Another way to think about it (for the mathematically inclined) is that |
830 | Another way to think about it (for the mathematically inclined) is that |
528 | ev_periodic will try to run the callback in this mode at the next possible |
831 | C<ev_periodic> will try to run the callback in this mode at the next possible |
529 | time where C<time = at (mod interval)>, regardless of any time jumps. |
832 | time where C<time = at (mod interval)>, regardless of any time jumps. |
530 | |
833 | |
531 | =item * manual reschedule mode (reschedule_cb = callback) |
834 | =item * manual reschedule mode (reschedule_cb = callback) |
532 | |
835 | |
533 | In this mode the values for C<interval> and C<at> are both being |
836 | In this mode the values for C<interval> and C<at> are both being |
534 | ignored. Instead, each time the periodic watcher gets scheduled, the |
837 | ignored. Instead, each time the periodic watcher gets scheduled, the |
535 | reschedule callback will be called with the watcher as first, and the |
838 | reschedule callback will be called with the watcher as first, and the |
536 | current time as second argument. |
839 | current time as second argument. |
537 | |
840 | |
538 | NOTE: I<This callback MUST NOT stop or destroy the periodic or any other |
841 | NOTE: I<This callback MUST NOT stop or destroy any periodic watcher, |
539 | periodic watcher, ever, or make any event loop modificstions>. If you need |
842 | ever, or make any event loop modifications>. If you need to stop it, |
540 | to stop it, return 1e30 (or so, fudge fudge) and stop it afterwards. |
843 | return C<now + 1e30> (or so, fudge fudge) and stop it afterwards (e.g. by |
|
|
844 | starting a prepare watcher). |
541 | |
845 | |
542 | Its prototype is c<ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
846 | Its prototype is C<ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
543 | ev_tstamp now)>, e.g.: |
847 | ev_tstamp now)>, e.g.: |
544 | |
848 | |
545 | static ev_tstamp my_rescheduler (struct ev_periodic *w, ev_tstamp now) |
849 | static ev_tstamp my_rescheduler (struct ev_periodic *w, ev_tstamp now) |
546 | { |
850 | { |
547 | return now + 60.; |
851 | return now + 60.; |
… | |
… | |
550 | It must return the next time to trigger, based on the passed time value |
854 | It must return the next time to trigger, based on the passed time value |
551 | (that is, the lowest time value larger than to the second argument). It |
855 | (that is, the lowest time value larger than to the second argument). It |
552 | will usually be called just before the callback will be triggered, but |
856 | will usually be called just before the callback will be triggered, but |
553 | might be called at other times, too. |
857 | might be called at other times, too. |
554 | |
858 | |
|
|
859 | NOTE: I<< This callback must always return a time that is later than the |
|
|
860 | passed C<now> value >>. Not even C<now> itself will do, it I<must> be larger. |
|
|
861 | |
555 | This can be used to create very complex timers, such as a timer that |
862 | This can be used to create very complex timers, such as a timer that |
556 | triggers on each midnight, local time. To do this, you would calculate the |
863 | triggers on each midnight, local time. To do this, you would calculate the |
557 | next midnight after C<now> and return the timestamp value for this. How you do this |
864 | next midnight after C<now> and return the timestamp value for this. How |
558 | is, again, up to you (but it is not trivial). |
865 | you do this is, again, up to you (but it is not trivial, which is the main |
|
|
866 | reason I omitted it as an example). |
559 | |
867 | |
560 | =back |
868 | =back |
561 | |
869 | |
562 | =item ev_periodic_again (loop, ev_periodic *) |
870 | =item ev_periodic_again (loop, ev_periodic *) |
563 | |
871 | |
… | |
… | |
566 | a different time than the last time it was called (e.g. in a crond like |
874 | a different time than the last time it was called (e.g. in a crond like |
567 | program when the crontabs have changed). |
875 | program when the crontabs have changed). |
568 | |
876 | |
569 | =back |
877 | =back |
570 | |
878 | |
|
|
879 | Example: call a callback every hour, or, more precisely, whenever the |
|
|
880 | system clock is divisible by 3600. The callback invocation times have |
|
|
881 | potentially a lot of jittering, but good long-term stability. |
|
|
882 | |
|
|
883 | static void |
|
|
884 | clock_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
|
|
885 | { |
|
|
886 | ... its now a full hour (UTC, or TAI or whatever your clock follows) |
|
|
887 | } |
|
|
888 | |
|
|
889 | struct ev_periodic hourly_tick; |
|
|
890 | ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
|
|
891 | ev_periodic_start (loop, &hourly_tick); |
|
|
892 | |
|
|
893 | Example: the same as above, but use a reschedule callback to do it: |
|
|
894 | |
|
|
895 | #include <math.h> |
|
|
896 | |
|
|
897 | static ev_tstamp |
|
|
898 | my_scheduler_cb (struct ev_periodic *w, ev_tstamp now) |
|
|
899 | { |
|
|
900 | return fmod (now, 3600.) + 3600.; |
|
|
901 | } |
|
|
902 | |
|
|
903 | ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
|
|
904 | |
|
|
905 | Example: call a callback every hour, starting now: |
|
|
906 | |
|
|
907 | struct ev_periodic hourly_tick; |
|
|
908 | ev_periodic_init (&hourly_tick, clock_cb, |
|
|
909 | fmod (ev_now (loop), 3600.), 3600., 0); |
|
|
910 | ev_periodic_start (loop, &hourly_tick); |
|
|
911 | |
|
|
912 | |
571 | =head2 ev_signal - signal me when a signal gets signalled |
913 | =head2 C<ev_signal> - signal me when a signal gets signalled |
572 | |
914 | |
573 | Signal watchers will trigger an event when the process receives a specific |
915 | Signal watchers will trigger an event when the process receives a specific |
574 | signal one or more times. Even though signals are very asynchronous, libev |
916 | signal one or more times. Even though signals are very asynchronous, libev |
575 | will try its best to deliver signals synchronously, i.e. as part of the |
917 | will try it's best to deliver signals synchronously, i.e. as part of the |
576 | normal event processing, like any other event. |
918 | normal event processing, like any other event. |
577 | |
919 | |
578 | You cna configure as many watchers as you like per signal. Only when the |
920 | You can configure as many watchers as you like per signal. Only when the |
579 | first watcher gets started will libev actually register a signal watcher |
921 | first watcher gets started will libev actually register a signal watcher |
580 | with the kernel (thus it coexists with your own signal handlers as long |
922 | with the kernel (thus it coexists with your own signal handlers as long |
581 | as you don't register any with libev). Similarly, when the last signal |
923 | as you don't register any with libev). Similarly, when the last signal |
582 | watcher for a signal is stopped libev will reset the signal handler to |
924 | watcher for a signal is stopped libev will reset the signal handler to |
583 | SIG_DFL (regardless of what it was set to before). |
925 | SIG_DFL (regardless of what it was set to before). |
… | |
… | |
591 | Configures the watcher to trigger on the given signal number (usually one |
933 | Configures the watcher to trigger on the given signal number (usually one |
592 | of the C<SIGxxx> constants). |
934 | of the C<SIGxxx> constants). |
593 | |
935 | |
594 | =back |
936 | =back |
595 | |
937 | |
|
|
938 | |
596 | =head2 ev_child - wait for pid status changes |
939 | =head2 C<ev_child> - wait for pid status changes |
597 | |
940 | |
598 | Child watchers trigger when your process receives a SIGCHLD in response to |
941 | Child watchers trigger when your process receives a SIGCHLD in response to |
599 | some child status changes (most typically when a child of yours dies). |
942 | some child status changes (most typically when a child of yours dies). |
600 | |
943 | |
601 | =over 4 |
944 | =over 4 |
… | |
… | |
605 | =item ev_child_set (ev_child *, int pid) |
948 | =item ev_child_set (ev_child *, int pid) |
606 | |
949 | |
607 | Configures the watcher to wait for status changes of process C<pid> (or |
950 | Configures the watcher to wait for status changes of process C<pid> (or |
608 | I<any> process if C<pid> is specified as C<0>). The callback can look |
951 | I<any> process if C<pid> is specified as C<0>). The callback can look |
609 | at the C<rstatus> member of the C<ev_child> watcher structure to see |
952 | at the C<rstatus> member of the C<ev_child> watcher structure to see |
610 | the status word (use the macros from C<sys/wait.h>). The C<rpid> member |
953 | the status word (use the macros from C<sys/wait.h> and see your systems |
611 | contains the pid of the process causing the status change. |
954 | C<waitpid> documentation). The C<rpid> member contains the pid of the |
|
|
955 | process causing the status change. |
612 | |
956 | |
613 | =back |
957 | =back |
614 | |
958 | |
|
|
959 | Example: try to exit cleanly on SIGINT and SIGTERM. |
|
|
960 | |
|
|
961 | static void |
|
|
962 | sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
|
|
963 | { |
|
|
964 | ev_unloop (loop, EVUNLOOP_ALL); |
|
|
965 | } |
|
|
966 | |
|
|
967 | struct ev_signal signal_watcher; |
|
|
968 | ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
|
|
969 | ev_signal_start (loop, &sigint_cb); |
|
|
970 | |
|
|
971 | |
615 | =head2 ev_idle - when you've got nothing better to do |
972 | =head2 C<ev_idle> - when you've got nothing better to do |
616 | |
973 | |
617 | Idle watchers trigger events when there are no other I/O or timer (or |
974 | Idle watchers trigger events when there are no other events are pending |
618 | periodic) events pending. That is, as long as your process is busy |
975 | (prepare, check and other idle watchers do not count). That is, as long |
619 | handling sockets or timeouts it will not be called. But when your process |
976 | as your process is busy handling sockets or timeouts (or even signals, |
620 | is idle all idle watchers are being called again and again - until |
977 | imagine) it will not be triggered. But when your process is idle all idle |
|
|
978 | watchers are being called again and again, once per event loop iteration - |
621 | stopped, that is, or your process receives more events. |
979 | until stopped, that is, or your process receives more events and becomes |
|
|
980 | busy. |
622 | |
981 | |
623 | The most noteworthy effect is that as long as any idle watchers are |
982 | The most noteworthy effect is that as long as any idle watchers are |
624 | active, the process will not block when waiting for new events. |
983 | active, the process will not block when waiting for new events. |
625 | |
984 | |
626 | Apart from keeping your process non-blocking (which is a useful |
985 | Apart from keeping your process non-blocking (which is a useful |
… | |
… | |
636 | kind. There is a C<ev_idle_set> macro, but using it is utterly pointless, |
995 | kind. There is a C<ev_idle_set> macro, but using it is utterly pointless, |
637 | believe me. |
996 | believe me. |
638 | |
997 | |
639 | =back |
998 | =back |
640 | |
999 | |
641 | =head2 prepare and check - your hooks into the event loop |
1000 | Example: dynamically allocate an C<ev_idle>, start it, and in the |
|
|
1001 | callback, free it. Alos, use no error checking, as usual. |
642 | |
1002 | |
|
|
1003 | static void |
|
|
1004 | idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
|
|
1005 | { |
|
|
1006 | free (w); |
|
|
1007 | // now do something you wanted to do when the program has |
|
|
1008 | // no longer asnything immediate to do. |
|
|
1009 | } |
|
|
1010 | |
|
|
1011 | struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle)); |
|
|
1012 | ev_idle_init (idle_watcher, idle_cb); |
|
|
1013 | ev_idle_start (loop, idle_cb); |
|
|
1014 | |
|
|
1015 | |
|
|
1016 | =head2 C<ev_prepare> and C<ev_check> - customise your event loop |
|
|
1017 | |
643 | Prepare and check watchers usually (but not always) are used in |
1018 | Prepare and check watchers are usually (but not always) used in tandem: |
644 | tandom. Prepare watchers get invoked before the process blocks and check |
1019 | prepare watchers get invoked before the process blocks and check watchers |
645 | watchers afterwards. |
1020 | afterwards. |
646 | |
1021 | |
647 | Their main purpose is to integrate other event mechanisms into libev. This |
1022 | Their main purpose is to integrate other event mechanisms into libev and |
648 | could be used, for example, to track variable changes, implement your own |
1023 | their use is somewhat advanced. This could be used, for example, to track |
649 | watchers, integrate net-snmp or a coroutine library and lots more. |
1024 | variable changes, implement your own watchers, integrate net-snmp or a |
|
|
1025 | coroutine library and lots more. |
650 | |
1026 | |
651 | This is done by examining in each prepare call which file descriptors need |
1027 | This is done by examining in each prepare call which file descriptors need |
652 | to be watched by the other library, registering ev_io watchers for them |
1028 | to be watched by the other library, registering C<ev_io> watchers for |
653 | and starting an ev_timer watcher for any timeouts (many libraries provide |
1029 | them and starting an C<ev_timer> watcher for any timeouts (many libraries |
654 | just this functionality). Then, in the check watcher you check for any |
1030 | provide just this functionality). Then, in the check watcher you check for |
655 | events that occured (by making your callbacks set soem flags for example) |
1031 | any events that occured (by checking the pending status of all watchers |
656 | and call back into the library. |
1032 | and stopping them) and call back into the library. The I/O and timer |
|
|
1033 | callbacks will never actually be called (but must be valid nevertheless, |
|
|
1034 | because you never know, you know?). |
657 | |
1035 | |
658 | As another example, the perl Coro module uses these hooks to integrate |
1036 | As another example, the Perl Coro module uses these hooks to integrate |
659 | coroutines into libev programs, by yielding to other active coroutines |
1037 | coroutines into libev programs, by yielding to other active coroutines |
660 | during each prepare and only letting the process block if no coroutines |
1038 | during each prepare and only letting the process block if no coroutines |
661 | are ready to run. |
1039 | are ready to run (it's actually more complicated: it only runs coroutines |
|
|
1040 | with priority higher than or equal to the event loop and one coroutine |
|
|
1041 | of lower priority, but only once, using idle watchers to keep the event |
|
|
1042 | loop from blocking if lower-priority coroutines are active, thus mapping |
|
|
1043 | low-priority coroutines to idle/background tasks). |
662 | |
1044 | |
663 | =over 4 |
1045 | =over 4 |
664 | |
1046 | |
665 | =item ev_prepare_init (ev_prepare *, callback) |
1047 | =item ev_prepare_init (ev_prepare *, callback) |
666 | |
1048 | |
667 | =item ev_check_init (ev_check *, callback) |
1049 | =item ev_check_init (ev_check *, callback) |
668 | |
1050 | |
669 | Initialises and configures the prepare or check watcher - they have no |
1051 | Initialises and configures the prepare or check watcher - they have no |
670 | parameters of any kind. There are C<ev_prepare_set> and C<ev_check_set> |
1052 | parameters of any kind. There are C<ev_prepare_set> and C<ev_check_set> |
671 | macros, but using them is utterly, utterly pointless. |
1053 | macros, but using them is utterly, utterly and completely pointless. |
672 | |
1054 | |
673 | =back |
1055 | =back |
|
|
1056 | |
|
|
1057 | Example: *TODO*. |
|
|
1058 | |
|
|
1059 | |
|
|
1060 | =head2 C<ev_embed> - when one backend isn't enough |
|
|
1061 | |
|
|
1062 | This is a rather advanced watcher type that lets you embed one event loop |
|
|
1063 | into another. |
|
|
1064 | |
|
|
1065 | There are primarily two reasons you would want that: work around bugs and |
|
|
1066 | prioritise I/O. |
|
|
1067 | |
|
|
1068 | As an example for a bug workaround, the kqueue backend might only support |
|
|
1069 | sockets on some platform, so it is unusable as generic backend, but you |
|
|
1070 | still want to make use of it because you have many sockets and it scales |
|
|
1071 | so nicely. In this case, you would create a kqueue-based loop and embed it |
|
|
1072 | into your default loop (which might use e.g. poll). Overall operation will |
|
|
1073 | be a bit slower because first libev has to poll and then call kevent, but |
|
|
1074 | at least you can use both at what they are best. |
|
|
1075 | |
|
|
1076 | As for prioritising I/O: rarely you have the case where some fds have |
|
|
1077 | to be watched and handled very quickly (with low latency), and even |
|
|
1078 | priorities and idle watchers might have too much overhead. In this case |
|
|
1079 | you would put all the high priority stuff in one loop and all the rest in |
|
|
1080 | a second one, and embed the second one in the first. |
|
|
1081 | |
|
|
1082 | As long as the watcher is started it will automatically handle events. The |
|
|
1083 | callback will be invoked whenever some events have been handled. You can |
|
|
1084 | set the callback to C<0> to avoid having to specify one if you are not |
|
|
1085 | interested in that. |
|
|
1086 | |
|
|
1087 | Also, there have not currently been made special provisions for forking: |
|
|
1088 | when you fork, you not only have to call C<ev_loop_fork> on both loops, |
|
|
1089 | but you will also have to stop and restart any C<ev_embed> watchers |
|
|
1090 | yourself. |
|
|
1091 | |
|
|
1092 | Unfortunately, not all backends are embeddable, only the ones returned by |
|
|
1093 | C<ev_embeddable_backends> are, which, unfortunately, does not include any |
|
|
1094 | portable one. |
|
|
1095 | |
|
|
1096 | So when you want to use this feature you will always have to be prepared |
|
|
1097 | that you cannot get an embeddable loop. The recommended way to get around |
|
|
1098 | this is to have a separate variables for your embeddable loop, try to |
|
|
1099 | create it, and if that fails, use the normal loop for everything: |
|
|
1100 | |
|
|
1101 | struct ev_loop *loop_hi = ev_default_init (0); |
|
|
1102 | struct ev_loop *loop_lo = 0; |
|
|
1103 | struct ev_embed embed; |
|
|
1104 | |
|
|
1105 | // see if there is a chance of getting one that works |
|
|
1106 | // (remember that a flags value of 0 means autodetection) |
|
|
1107 | loop_lo = ev_embeddable_backends () & ev_recommended_backends () |
|
|
1108 | ? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ()) |
|
|
1109 | : 0; |
|
|
1110 | |
|
|
1111 | // if we got one, then embed it, otherwise default to loop_hi |
|
|
1112 | if (loop_lo) |
|
|
1113 | { |
|
|
1114 | ev_embed_init (&embed, 0, loop_lo); |
|
|
1115 | ev_embed_start (loop_hi, &embed); |
|
|
1116 | } |
|
|
1117 | else |
|
|
1118 | loop_lo = loop_hi; |
|
|
1119 | |
|
|
1120 | =over 4 |
|
|
1121 | |
|
|
1122 | =item ev_embed_init (ev_embed *, callback, struct ev_loop *loop) |
|
|
1123 | |
|
|
1124 | =item ev_embed_set (ev_embed *, callback, struct ev_loop *loop) |
|
|
1125 | |
|
|
1126 | Configures the watcher to embed the given loop, which must be embeddable. |
|
|
1127 | |
|
|
1128 | =back |
|
|
1129 | |
674 | |
1130 | |
675 | =head1 OTHER FUNCTIONS |
1131 | =head1 OTHER FUNCTIONS |
676 | |
1132 | |
677 | There are some other fucntions of possible interest. Described. Here. Now. |
1133 | There are some other functions of possible interest. Described. Here. Now. |
678 | |
1134 | |
679 | =over 4 |
1135 | =over 4 |
680 | |
1136 | |
681 | =item ev_once (loop, int fd, int events, ev_tstamp timeout, callback) |
1137 | =item ev_once (loop, int fd, int events, ev_tstamp timeout, callback) |
682 | |
1138 | |
683 | This function combines a simple timer and an I/O watcher, calls your |
1139 | This function combines a simple timer and an I/O watcher, calls your |
684 | callback on whichever event happens first and automatically stop both |
1140 | callback on whichever event happens first and automatically stop both |
685 | watchers. This is useful if you want to wait for a single event on an fd |
1141 | watchers. This is useful if you want to wait for a single event on an fd |
686 | or timeout without havign to allocate/configure/start/stop/free one or |
1142 | or timeout without having to allocate/configure/start/stop/free one or |
687 | more watchers yourself. |
1143 | more watchers yourself. |
688 | |
1144 | |
689 | If C<fd> is less than 0, then no I/O watcher will be started and events is |
1145 | If C<fd> is less than 0, then no I/O watcher will be started and events |
690 | ignored. Otherwise, an ev_io watcher for the given C<fd> and C<events> set |
1146 | is being ignored. Otherwise, an C<ev_io> watcher for the given C<fd> and |
691 | will be craeted and started. |
1147 | C<events> set will be craeted and started. |
692 | |
1148 | |
693 | If C<timeout> is less than 0, then no timeout watcher will be |
1149 | If C<timeout> is less than 0, then no timeout watcher will be |
694 | started. Otherwise an ev_timer watcher with after = C<timeout> (and repeat |
1150 | started. Otherwise an C<ev_timer> watcher with after = C<timeout> (and |
695 | = 0) will be started. |
1151 | repeat = 0) will be started. While C<0> is a valid timeout, it is of |
|
|
1152 | dubious value. |
696 | |
1153 | |
697 | The callback has the type C<void (*cb)(int revents, void *arg)> and |
1154 | The callback has the type C<void (*cb)(int revents, void *arg)> and gets |
698 | gets passed an events set (normally a combination of EV_ERROR, EV_READ, |
1155 | passed an C<revents> set like normal event callbacks (a combination of |
699 | EV_WRITE or EV_TIMEOUT) and the C<arg> value passed to C<ev_once>: |
1156 | C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMEOUT>) and the C<arg> |
|
|
1157 | value passed to C<ev_once>: |
700 | |
1158 | |
701 | static void stdin_ready (int revents, void *arg) |
1159 | static void stdin_ready (int revents, void *arg) |
702 | { |
1160 | { |
703 | if (revents & EV_TIMEOUT) |
1161 | if (revents & EV_TIMEOUT) |
704 | /* doh, nothing entered */ |
1162 | /* doh, nothing entered */; |
705 | else if (revents & EV_READ) |
1163 | else if (revents & EV_READ) |
706 | /* stdin might have data for us, joy! */ |
1164 | /* stdin might have data for us, joy! */; |
707 | } |
1165 | } |
708 | |
1166 | |
709 | ev_once (STDIN_FILENO, EV_READm 10., stdin_ready, 0); |
1167 | ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0); |
710 | |
1168 | |
711 | =item ev_feed_event (loop, watcher, int events) |
1169 | =item ev_feed_event (loop, watcher, int events) |
712 | |
1170 | |
713 | Feeds the given event set into the event loop, as if the specified event |
1171 | Feeds the given event set into the event loop, as if the specified event |
714 | has happened for the specified watcher (which must be a pointer to an |
1172 | had happened for the specified watcher (which must be a pointer to an |
715 | initialised but not necessarily active event watcher). |
1173 | initialised but not necessarily started event watcher). |
716 | |
1174 | |
717 | =item ev_feed_fd_event (loop, int fd, int revents) |
1175 | =item ev_feed_fd_event (loop, int fd, int revents) |
718 | |
1176 | |
719 | Feed an event on the given fd, as if a file descriptor backend detected it. |
1177 | Feed an event on the given fd, as if a file descriptor backend detected |
|
|
1178 | the given events it. |
720 | |
1179 | |
721 | =item ev_feed_signal_event (loop, int signum) |
1180 | =item ev_feed_signal_event (loop, int signum) |
722 | |
1181 | |
723 | Feed an event as if the given signal occured (loop must be the default loop!). |
1182 | Feed an event as if the given signal occured (loop must be the default loop!). |
724 | |
1183 | |
725 | =back |
1184 | =back |
726 | |
1185 | |
|
|
1186 | |
|
|
1187 | =head1 LIBEVENT EMULATION |
|
|
1188 | |
|
|
1189 | Libev offers a compatibility emulation layer for libevent. It cannot |
|
|
1190 | emulate the internals of libevent, so here are some usage hints: |
|
|
1191 | |
|
|
1192 | =over 4 |
|
|
1193 | |
|
|
1194 | =item * Use it by including <event.h>, as usual. |
|
|
1195 | |
|
|
1196 | =item * The following members are fully supported: ev_base, ev_callback, |
|
|
1197 | ev_arg, ev_fd, ev_res, ev_events. |
|
|
1198 | |
|
|
1199 | =item * Avoid using ev_flags and the EVLIST_*-macros, while it is |
|
|
1200 | maintained by libev, it does not work exactly the same way as in libevent (consider |
|
|
1201 | it a private API). |
|
|
1202 | |
|
|
1203 | =item * Priorities are not currently supported. Initialising priorities |
|
|
1204 | will fail and all watchers will have the same priority, even though there |
|
|
1205 | is an ev_pri field. |
|
|
1206 | |
|
|
1207 | =item * Other members are not supported. |
|
|
1208 | |
|
|
1209 | =item * The libev emulation is I<not> ABI compatible to libevent, you need |
|
|
1210 | to use the libev header file and library. |
|
|
1211 | |
|
|
1212 | =back |
|
|
1213 | |
|
|
1214 | =head1 C++ SUPPORT |
|
|
1215 | |
|
|
1216 | TBD. |
|
|
1217 | |
727 | =head1 AUTHOR |
1218 | =head1 AUTHOR |
728 | |
1219 | |
729 | Marc Lehmann <libev@schmorp.de>. |
1220 | Marc Lehmann <libev@schmorp.de>. |
730 | |
1221 | |