Author: stas Date: Thu Dec 2 16:51:28 2004 New Revision: 109609 URL: http://svn.apache.org/viewcvs?view=rev&rev=109609 Log: signal handlers? not with apache2
Modified: perl/modperl/docs/trunk/src/docs/2.0/user/coding/coding.pod Modified: perl/modperl/docs/trunk/src/docs/2.0/user/coding/coding.pod Url: http://svn.apache.org/viewcvs/perl/modperl/docs/trunk/src/docs/2.0/user/coding/coding.pod?view=diff&rev=109609&p1=perl/modperl/docs/trunk/src/docs/2.0/user/coding/coding.pod&r1=109608&p2=perl/modperl/docs/trunk/src/docs/2.0/user/coding/coding.pod&r2=109609 ============================================================================== --- perl/modperl/docs/trunk/src/docs/2.0/user/coding/coding.pod (original) +++ perl/modperl/docs/trunk/src/docs/2.0/user/coding/coding.pod Thu Dec 2 16:51:28 2004 @@ -441,6 +441,39 @@ +=head2 Using Signal Handlers + +3rd party Apache 2 modules should avoid using code relying on +signals. This is because typical signal use is not thread-safe and +modules which rely on signals may not work portably. Certain signals +may still work for non-threaded mpms. For example C<alarm()> can be +used under prefork MPM, but it won't work on any other MPM. Moreover +the Apache developers don'tq guarantee that the signals that currently +happen to work will continue to do so in the future Apache +releases. So use them at your own risk. + +It should be possible to rework the code using signals to use an +alternative solution, which works under threads. For example if you +were using C<alarm()> to trap potentially long running I/O, you can +modify the I/O logic for select/poll usage (or if you use APR I/O then +set timeouts on the apr pipes or sockets). For example, Apache 1.3 on +Unix made blocking I/O calls and relied on the parent process to send +the SIGALRM signal to break it out of the I/O after a timeout expired. +With Apache 2.0, APR support for timeouts on I/O operations is used so +that signals or other thread-unsafe mechanisms are not necessary. + +CPU timeout handling is another example. It can be accomplished by +modifying the computation logic to explicitly check for the timeout at +intervals. + + + + + + + + + =head1 Perl Specifics in the mod_perl Environment In the following sections we discuss the specifics of Perl behavior --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
