Retrieve the current value of the specified pixmap property of type void*
#include <screen/screen.h>
int screen_get_pixmap_property_pv(screen_pixmap_t pix, int pname, void **param)
Function Type: Flushing Execution
Note [1]: When you're retrieving this property, the function type is Immediate Execution.
Note [2]: When you're retrieving this property, Screen locally allocates resources to track the group that you retrieve. Therefore, you must call screen_destroy_group() to free these resources when you no longer need to use the group in your local context.
0 if successful, or -1 if an error occurred (errno is set; refer to errno.h for more details).