| … | |
… | |
| 196 | See the description of C<ev_embed> watchers for more info. |
196 | See the description of C<ev_embed> watchers for more info. |
| 197 | |
197 | |
| 198 | =item ev_set_allocator (void *(*cb)(void *ptr, long size)) |
198 | =item ev_set_allocator (void *(*cb)(void *ptr, long size)) |
| 199 | |
199 | |
| 200 | Sets the allocation function to use (the prototype is similar - the |
200 | Sets the allocation function to use (the prototype is similar - the |
| 201 | semantics is identical - to the realloc C function). It is used to |
201 | semantics are identical to the C<realloc> C89/SuS/POSIX function). It is |
| 202 | allocate and free memory (no surprises here). If it returns zero when |
202 | used to allocate and free memory (no surprises here). If it returns zero |
| 203 | memory needs to be allocated, the library might abort or take some |
203 | when memory needs to be allocated (C<size != 0>), the library might abort |
| 204 | potentially destructive action. The default is your system realloc |
204 | or take some potentially destructive action. |
| 205 | function. |
205 | |
|
|
206 | Since some systems (at least OpenBSD and Darwin) fail to implement |
|
|
207 | correct C<realloc> semantics, libev will use a wrapper around the system |
|
|
208 | C<realloc> and C<free> functions by default. |
| 206 | |
209 | |
| 207 | You could override this function in high-availability programs to, say, |
210 | You could override this function in high-availability programs to, say, |
| 208 | free some memory if it cannot allocate memory, to use a special allocator, |
211 | free some memory if it cannot allocate memory, to use a special allocator, |
| 209 | or even to sleep a while and retry until some memory is available. |
212 | or even to sleep a while and retry until some memory is available. |
| 210 | |
213 | |
| 211 | Example: Replace the libev allocator with one that waits a bit and then |
214 | Example: Replace the libev allocator with one that waits a bit and then |
| 212 | retries). |
215 | retries (example requires a standards-compliant C<realloc>). |
| 213 | |
216 | |
| 214 | static void * |
217 | static void * |
| 215 | persistent_realloc (void *ptr, size_t size) |
218 | persistent_realloc (void *ptr, size_t size) |
| 216 | { |
219 | { |
| 217 | for (;;) |
220 | for (;;) |
| … | |
… | |
| 1631 | When C<inotify (7)> support has been compiled into libev (generally only |
1634 | When C<inotify (7)> support has been compiled into libev (generally only |
| 1632 | available on Linux) and present at runtime, it will be used to speed up |
1635 | available on Linux) and present at runtime, it will be used to speed up |
| 1633 | change detection where possible. The inotify descriptor will be created lazily |
1636 | change detection where possible. The inotify descriptor will be created lazily |
| 1634 | when the first C<ev_stat> watcher is being started. |
1637 | when the first C<ev_stat> watcher is being started. |
| 1635 | |
1638 | |
| 1636 | Inotify presense does not change the semantics of C<ev_stat> watchers |
1639 | Inotify presence does not change the semantics of C<ev_stat> watchers |
| 1637 | except that changes might be detected earlier, and in some cases, to avoid |
1640 | except that changes might be detected earlier, and in some cases, to avoid |
| 1638 | making regular C<stat> calls. Even in the presense of inotify support |
1641 | making regular C<stat> calls. Even in the presence of inotify support |
| 1639 | there are many cases where libev has to resort to regular C<stat> polling. |
1642 | there are many cases where libev has to resort to regular C<stat> polling. |
| 1640 | |
1643 | |
| 1641 | (There is no support for kqueue, as apparently it cannot be used to |
1644 | (There is no support for kqueue, as apparently it cannot be used to |
| 1642 | implement this functionality, due to the requirement of having a file |
1645 | implement this functionality, due to the requirement of having a file |
| 1643 | descriptor open on the object at all times). |
1646 | descriptor open on the object at all times). |
| … | |
… | |
| 2375 | |
2378 | |
| 2376 | =item * Priorities are not currently supported. Initialising priorities |
2379 | =item * Priorities are not currently supported. Initialising priorities |
| 2377 | will fail and all watchers will have the same priority, even though there |
2380 | will fail and all watchers will have the same priority, even though there |
| 2378 | is an ev_pri field. |
2381 | is an ev_pri field. |
| 2379 | |
2382 | |
|
|
2383 | =item * In libevent, the last base created gets the signals, in libev, the |
|
|
2384 | first base created (== the default loop) gets the signals. |
|
|
2385 | |
| 2380 | =item * Other members are not supported. |
2386 | =item * Other members are not supported. |
| 2381 | |
2387 | |
| 2382 | =item * The libev emulation is I<not> ABI compatible to libevent, you need |
2388 | =item * The libev emulation is I<not> ABI compatible to libevent, you need |
| 2383 | to use the libev header file and library. |
2389 | to use the libev header file and library. |
| 2384 | |
2390 | |
| … | |
… | |
| 3254 | calling select (O(n²)) will likely make this unworkable. |
3260 | calling select (O(n²)) will likely make this unworkable. |
| 3255 | |
3261 | |
| 3256 | =back |
3262 | =back |
| 3257 | |
3263 | |
| 3258 | |
3264 | |
|
|
3265 | =head1 PORTABILITY REQUIREMENTS |
|
|
3266 | |
|
|
3267 | In addition to a working ISO-C implementation, libev relies on a few |
|
|
3268 | additional extensions: |
|
|
3269 | |
|
|
3270 | =over 4 |
|
|
3271 | |
|
|
3272 | =item C<sig_atomic_t volatile> must be thread-atomic as well |
|
|
3273 | |
|
|
3274 | The type C<sig_atomic_t volatile> (or whatever is defined as |
|
|
3275 | C<EV_ATOMIC_T>) must be atomic w.r.t. accesses from different |
|
|
3276 | threads. This is not part of the specification for C<sig_atomic_t>, but is |
|
|
3277 | believed to be sufficiently portable. |
|
|
3278 | |
|
|
3279 | =item C<sigprocmask> must work in a threaded environment |
|
|
3280 | |
|
|
3281 | Libev uses C<sigprocmask> to temporarily block signals. This is not |
|
|
3282 | allowed in a threaded program (C<pthread_sigmask> has to be used). Typical |
|
|
3283 | pthread implementations will either allow C<sigprocmask> in the "main |
|
|
3284 | thread" or will block signals process-wide, both behaviours would |
|
|
3285 | be compatible with libev. Interaction between C<sigprocmask> and |
|
|
3286 | C<pthread_sigmask> could complicate things, however. |
|
|
3287 | |
|
|
3288 | The most portable way to handle signals is to block signals in all threads |
|
|
3289 | except the initial one, and run the default loop in the initial thread as |
|
|
3290 | well. |
|
|
3291 | |
|
|
3292 | =back |
|
|
3293 | |
|
|
3294 | If you know of other additional requirements drop me a note. |
|
|
3295 | |
|
|
3296 | |
| 3259 | =head1 AUTHOR |
3297 | =head1 AUTHOR |
| 3260 | |
3298 | |
| 3261 | Marc Lehmann <libev@schmorp.de>. |
3299 | Marc Lehmann <libev@schmorp.de>. |
| 3262 | |
3300 | |
