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| -rw-r--r-- | Changes | 3 | ||||
| -rw-r--r-- | ev.pod | 55 |
2 files changed, 58 insertions, 0 deletions
@@ -1,5 +1,8 @@ Revision history for libev, a high-performance and full-featured event loop. +TODO: move some other examples to common idioms? combining watchers, +thread usage, coroutine switch? + 4.01 Fri Nov 5 21:51:29 CET 2010 - automake fucked it up, apparently, --add-missing -f is not quite enough to make it update its files, so 4.00 didn't install ev++.h and @@ -3369,6 +3369,56 @@ loop!). =back +=head1 COMMON OR USEFUL IDIOMS (OR BOTH) + +This section explains some common idioms that are not immediately +obvious. Note that examples are sprinkled over the whole manual, and this +section only contains stuff that wouldn't fit anywhere else. + +=over 4 + +=item Model/nested event loop invocations and exit conditions. + +Often (especially in GUI toolkits) there are places where you have +I<modal> interaction, which is most easily implemented by recursively +invoking C<ev_run>. + +This brings the problem of exiting - a callback might want to finish the +main C<ev_run> call, but not the nested one (e.g. user clicked "Quit", but +a modal "Are you sure?" dialog is still waiting), or just the nested one +and not the main one (e.g. user clocked "Ok" in a modal dialog), or some +other combination: In these cases, C<ev_break> will not work alone. + +The solution is to maintain "break this loop" variable for each C<ev_run> +invocation, and use a loop around C<ev_run> until the condition is +triggered, using C<EVRUN_ONCE>: + + // main loop + int exit_main_loop = 0; + + while (!exit_main_loop) + ev_run (EV_DEFAULT_ EVRUN_ONCE); + + // in a model watcher + int exit_nested_loop = 0; + + while (!exit_nested_loop) + ev_run (EV_A_ EVRUN_ONCE); + +To exit from any of these loops, just set the corresponding exit variable: + + // exit modal loop + exit_nested_loop = 1; + + // exit main program, after modal loop is finished + exit_main_loop = 1; + + // exit both + exit_main_loop = exit_nested_loop = 1; + +=back + + =head1 LIBEVENT EMULATION Libev offers a compatibility emulation layer for libevent. It cannot @@ -3376,6 +3426,11 @@ emulate the internals of libevent, so here are some usage hints: =over 4 +=item * Only the libevent-1.4.1-beta API is being emulated. + +This was the newest libevent version available when libev was implemented, +and is still mostly uncanged in 2010. + =item * Use it by including <event.h>, as usual. =item * The following members are fully supported: ev_base, ev_callback, |