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 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()