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Comparing Guard/Guard.pm (file contents):
Revision 1.10 by root, Sat Dec 13 18:50:31 2008 UTC vs.
Revision 1.13 by root, Sat Dec 13 19:14:58 2008 UTC

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34 34
35=cut 35=cut
36 36
37package Guard; 37package Guard;
38 38
39no warnings;
40
39BEGIN { 41BEGIN {
40 $VERSION = '0.1'; 42 $VERSION = '0.5';
41 @ISA = qw(Exporter); 43 @ISA = qw(Exporter);
42 @EXPORT = qw(guard scope_guard); 44 @EXPORT = qw(guard scope_guard);
43 45
44 require Exporter; 46 require Exporter;
45 47
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133 135
134The advantage of doing this with a guard instead of simply calling C<< 136The advantage of doing this with a guard instead of simply calling C<<
135$sem->down >> in the callback is that you can opt not to create the timer, 137$sem->down >> in the callback is that you can opt not to create the timer,
136or your code can throw an exception before it can create the timer, or you 138or your code can throw an exception before it can create the timer, or you
137can create multiple timers or other event watchers and only when the last 139can create multiple timers or other event watchers and only when the last
138one gets executed will the lock be unlocked. 140one gets executed will the lock be unlocked. Using the C<guard>, you do
141not have to worry about catching all the places where you have to unlock
142the semaphore.
139 143
140=item Guard::cancel $guard 144=item $guard->cancel
141 145
142Calling this function will "disable" the guard object returned by the 146Calling this function will "disable" the guard object returned by the
143C<guard> function, i.e. it will free the BLOCK originally passed to 147C<guard> function, i.e. it will free the BLOCK originally passed to
144C<guard >and will arrange for the BLOCK not to be executed. 148C<guard >and will arrange for the BLOCK not to be executed.
145 149
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167Therefore, whenever a guard block throws an exception, it will be caught, 171Therefore, whenever a guard block throws an exception, it will be caught,
168and this module will call the code reference stored in C<$Guard::DIED> 172and this module will call the code reference stored in C<$Guard::DIED>
169(with C<$@> set to the actual exception), which is similar to how most 173(with C<$@> set to the actual exception), which is similar to how most
170event loops handle this case. 174event loops handle this case.
171 175
176The default for C<$Guard::DIED> is to call C<warn "$@">.
177
178The C<$@> variable will be restored to its value before the guard call in
179all cases, so guards will not disturb C<$@> in any way.
180
172The code reference stored in C<$Guard::DIED> should not die (behaviour is 181The code reference stored in C<$Guard::DIED> should not die (behaviour is
173not guaranteed, but right now, the exception will simply be ignored). 182not guaranteed, but right now, the exception will simply be ignored).
174
175The default for C<$Guard::DIED> is to call C<warn "$@">.
176 183
177=head1 AUTHOR 184=head1 AUTHOR
178 185
179 Marc Lehmann <schmorp@schmorp.de> 186 Marc Lehmann <schmorp@schmorp.de>
180 http://home.schmorp.de/ 187 http://home.schmorp.de/

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