EFL Threading example 1

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EFL Threading example 1

You can use threads with Elementary (and EFL) but you need to be careful to only use eina or eet calls inside a thread.

Other libraries are not totally threadsafe except for some specific ecore calls designed for working from threads like the ecore_pipe_write() and ecore_thread calls.

Below is an example of how to use EFL calls from a native thread you have already created. You have to put the EFL calls inside the critical block between ecore_thread_main_loop_begin() and ecore_thread_main_loop_end() which ensure you gain a lock on the mainloop. Beware that this requires that the thread WAIT to synchronize with the mainloop at the beginning of the critical section. It is highly suggested you use as few of these in your thread as possible and probably put just a single ecore_thread_main_loop_begin() / ecore_thread_main_loop_end() section at the end of the threads calculation or work when it is done and would otherwise exit to sit idle.

For a progression of examples that become more complex and show other ways to use threading with EFL, please see:

EFL Threading example 2

EFL Threading example 3

EFL Threading example 4

EFL Threading example 5

EFL Threading example 6

//Compile with:
//gcc -o efl_thread_1 efl_thread_1.c -g `pkg-config --cflags --libs elementary`
#include <Elementary.h>
#include <pthread.h>
static Evas_Object *win = NULL;
static Evas_Object *rect = NULL;
static pthread_t thread_id;
// BEGIN - code running in my custom pthread instance
//
static void *
my_thread_run(void *arg EINA_UNUSED)
{
double t = 0.0;
for (;;)
{
ecore_thread_main_loop_begin(); // begin critical
{ // indented for illustration of "critical" block
Evas_Coord x, y;
x = 200 + (200 * sin(t));
y = 200 + (200 * cos(t));
evas_object_move(rect, x - 50, y - 50);
}
ecore_thread_main_loop_end(); // end critical
usleep(1000);
t += 0.02;
}
return NULL;
}
//
// END - code running in my custom pthread instance
static void
my_thread_new(void)
{
pthread_attr_t attr;
if (pthread_attr_init(&attr) != 0)
perror("pthread_attr_init");
if (pthread_create(&thread_id, &attr, my_thread_run, NULL) != 0)
perror("pthread_create");
}
// on window delete - cancel thread then delete window and exit mainloop
static void
del(void *data EINA_UNUSED, Evas_Object *obj EINA_UNUSED, void *event_info EINA_UNUSED)
{
exit(0);
}
EAPI_MAIN int
elm_main(int argc EINA_UNUSED, char **argv EINA_UNUSED)
{
Evas_Object *o;
win = elm_win_util_standard_add("efl-thread-1", "EFL Thread 1");
evas_object_smart_callback_add(win, "delete,request", del, NULL);
o = evas_object_rectangle_add(evas_object_evas_get(win));
evas_object_color_set(o, 50, 80, 180, 255);
evas_object_resize(o, 100, 100);
evas_object_show(o);
rect = o;
// create custom thread to do some "work on the side"
my_thread_new();
evas_object_resize(win, 400, 400);
evas_object_show(win);
elm_run();
return 0;
}
ELM_MAIN()
Evas_Coord
int Evas_Coord
Type used for coordinates (in pixels, int).
Definition: Evas_Common.h:116
ecore_thread_main_loop_begin
EAPI int ecore_thread_main_loop_begin(void)
This function suspends the main loop in a know state.
Definition: ecore.c:685
ecore_thread_main_loop_end
EAPI int ecore_thread_main_loop_end(void)
Unlocks the main loop.
Definition: ecore.c:735
EINA_UNUSED
#define EINA_UNUSED
Used to indicate that a function parameter is purposely unused.
Definition: eina_types.h:339
ELM_MAIN
#define ELM_MAIN()
macro to be used after the elm_main() function
Definition: elm_general.h:556
elm_run
void elm_run(void)
Run Elementary's main loop.
Definition: elm_main.c:1357
elm_win_util_standard_add
Evas_Object * elm_win_util_standard_add(const char *name, const char *title)
Adds a window object with standard setup.
Definition: efl_ui_win.c:9582
evas_object_show
EVAS_API void evas_object_show(Evas_Object *eo_obj)
Makes the given Evas object visible.
Definition: evas_object_main.c:1814
evas_object_color_set
EVAS_API void evas_object_color_set(Evas_Object *obj, int r, int g, int b, int a)
Sets the general/main color of the given Evas object to the given one.
Definition: evas_object_main.c:2024
evas_object_move
EVAS_API void evas_object_move(Evas_Object *obj, Evas_Coord x, Evas_Coord y)
Move the given Evas object to the given location inside its canvas' viewport.
Definition: evas_object_main.c:1171
evas_object_evas_get
EVAS_API Evas * evas_object_evas_get(const Eo *eo_obj)
Get the Evas to which this object belongs to.
Definition: evas_object_main.c:2662
Evas_Object
Efl_Canvas_Object Evas_Object
An Evas Object handle.
Definition: Evas_Common.h:185
evas_object_resize
EVAS_API void evas_object_resize(Evas_Object *obj, Evas_Coord w, Evas_Coord h)
Changes the size of the given Evas object.
Definition: evas_object_main.c:1236
evas_object_rectangle_add
EVAS_API Evas_Object * evas_object_rectangle_add(Evas *e)
Adds a rectangle to the given evas.
Definition: evas_object_rectangle.c:78
evas_object_smart_callback_add
EVAS_API void evas_object_smart_callback_add(Evas_Object *eo_obj, const char *event, Evas_Smart_Cb func, const void *data)
Add (register) a callback function to the smart event specified by event on the smart object obj.
Definition: evas_object_smart.c:1040