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ecore/poller - Add a poller example and its explanation.
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@ -9,6 +9,7 @@
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* @li @ref ecore_job_example_c
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* @li @ref ecore_event_example_c
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* @li @ref ecore_fd_handler_example_c
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* @li @ref ecore_poller_example_c
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*
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*/
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@ -391,6 +392,74 @@
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* the API usage, since Ecore would already do it for us on its shutdown.
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*/
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/**
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* @page ecore_poller_example_c ecore poller - Repetitive polling tasks
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* @dontinclude ecore_poller_example.c
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*
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* This example show how to setup, and explains how an @ref Ecore_Poller is
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* called. You can @ref ecore_poller_example.c "see the full source code here".
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*
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* In this example we store the initial time of the program just to use as
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* comparison to the time when the poller callbacks are called. It will be
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* stored in @c _initial_time :
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*
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* @until initial_time
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*
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* Then next step is to define the poller callback. This callback assumes that a
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* @c data pointer is passed to it on creation, and is a string just used to
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* identify the poller. The callback prints this string and the time since the
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* program started, and returns @ref ECORE_CALLBACK_RENEW to keep being called.
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*
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* @until }
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*
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* Now in the main function we initialize Ecore, and save the initial time of
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* the program, so we can compare it later with the time that the pollers are
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* being called:
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*
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* @until initial_time
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*
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* Then we change the poll interval to 0.3 seconds (the default is 0.125
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* seconds) just to show the API usage.
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*
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* Finally, we create two pollers, one that will be called every 4 ticks, and
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* another one that will be called every 8 ticks. This means the the first
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* poller interval will be around 1.2 seconds, and the second one will be
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* around 2.4 seconds. But the most important point is: since the second poller
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* interval is a multiple of the first one, they will be always synchronized.
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* Ecore calls pollers that are in the "same tick" together. It doesn't go back
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* to the main loop and check if there's another poller to execute at this
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* time, but instead it calls all the pollers registered to this "tick" at the
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* same time. See the description of ecore_poller_add() for more details. This
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* is easy to see in the time printed by both of them.
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*
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* If instead of two synchronized pollers, we were using two different timers,
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* one with interval of 1.2 seconds and another one with an interval of 2.4
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* seconds, there would be no guarantee that they would be totally in sync. Some
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* delay in the execution of another task, or even in the task called in the
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* callback, could make them get out of sync, forcing Ecore's main loop to wake
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* up more than necessary.
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*
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* Well, this is the code that create these two pollers and set the poll
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* interval, then starts the main loop:
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*
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* @until ecore_main_loop_begin
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*
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* If you hit CTRL-C during the execution of the program, the main loop will
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* quit, since there are some signal handlers already set by default to do this.
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* So after the main loop begin call, we change the second poller's interval to
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* 16 ticks, so it will happen each 4.8 seconds (or each 4 times that the first
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* poller is called).
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*
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* This means: the program is started, the first poller is called each 4 ticks
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* and the second is called each 8 ticks. After CTRL-C is used, the second
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* poller will be called each 16 ticks.
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*
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* @until }
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*
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* The rest of the program is just deleting the pollers and shutting down the
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* library.
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*/
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/**
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* @example ecore_idler_example.c
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* This example shows when @ref Ecore_Idler, @ref Ecore_Idle_Enterer and @ref
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* @ref ecore_fd_handler_example_c "the explanation here".
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*/
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/**
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* @example ecore_poller_example.c
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* This example shows how to setup and use a poller. See
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* @ref ecore_poller_example_c "the explanation here".
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*/
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/**
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* @example ecore_event_example.c
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* This example shows how to setup, change, and delete event handlers. See
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@ -13,6 +13,7 @@ LDADD = \
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SRCS = \
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ecore_fd_handler_example.c \
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ecore_poller_example.c \
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ecore_event_example.c \
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ecore_idler_example.c \
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ecore_timer_example.c \
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@ -37,6 +38,7 @@ endif
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if EFL_BUILD_EXAMPLES
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pkglib_PROGRAMS += \
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ecore_fd_handler_example \
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ecore_poller_example \
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ecore_event_example \
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ecore_idler_example \
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ecore_job_example \
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@ -0,0 +1,47 @@
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#include <Ecore.h>
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#include <unistd.h>
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static double _initial_time = 0;
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static Eina_Bool
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_poller_print_cb(void *data)
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{
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char *str = data;
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printf("Ecore Poller '%s' callback called after %0.3f seconds.\n",
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str, ecore_time_get() - _initial_time);
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return ECORE_CALLBACK_RENEW;
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}
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int main(int argc, char **argv)
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{
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double interval = 0.3; // tick each 0.3 seconds
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Ecore_Poller *poller1, *poller2;
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char *str1 = "poller1";
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char *str2 = "poller2";
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if (!ecore_init())
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{
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printf("ERROR: Cannot init Ecore!\n");
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return -1;
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}
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_initial_time = ecore_time_get();
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ecore_poller_poll_interval_set(ECORE_POLLER_CORE, interval);
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poller1 = ecore_poller_add(ECORE_POLLER_CORE, 4, _poller_print_cb, str1);
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poller2 = ecore_poller_add(ECORE_POLLER_CORE, 8, _poller_print_cb, str2);
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ecore_main_loop_begin();
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printf("changing poller2 interval to 16\n");
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ecore_poller_poller_interval_set(poller2, 16);
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ecore_main_loop_begin();
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ecore_poller_del(poller1);
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ecore_poller_del(poller2);
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ecore_shutdown();
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}
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