How to wait an input without stop the program in Xlib - c

Question

The problem is this, I, am writing a chip 8 emulator in C, and i am using a library that use Xlib, for writing sprites attending input etc, the method that the library have for wait an input is this:
char gfx_wait(){
XEvent event;
gfx_flush();
while(1) {
XNextEvent(gfx_display,&event);
if(event.type==KeyPress) {
saved_xpos = event.xkey.x;
saved_ypos = event.xkey.y;
return XLookupKeysym(&event.xkey,0);
} else if(event.type==ButtonPress) {
saved_xpos = event.xkey.x;
saved_ypos = event.xkey.y;
return event.xbutton.button;
}
}
}
when i call this method the program stops waiting for input, I, need a methods that is called just when i press or release a button.

Answer 1

I just solve my problem, using this function :
int gfx_event_waiting(unsigned char *ch)
{
XEvent event;
gfx_flush();
while (1) {
if(XCheckMaskEvent(gfx_display,-1,&event)) {
if(event.type==KeyPress) {
*ch = XLookupKeysym(&event.xkey,0);
return 1;
}else if(event.type==KeyRelease){
return 1;
}else if (event.type==ButtonPress) {
return 1;
} else {
return 0;
}
} else {
return 0;
}
}
}
and this is the main :
int
main(int argc, char *argv[])
{
int x;
int i;
unsigned char key_pressed,key_released;
Init();
LoadRom(SELECTED_ROM);
gfx_open(WIDTH,HEIGHT,"Chip 8 Emulator");
gfx_color(255,250,250);
for(;;){
if(!gfx_event_waiting(&key_pressed)){
opcode_cycle();
key_wait(key_released,0);
#if DEBUG
printf("# %d | %c #",x,key_pressed);
#endif
key_wait(key_pressed,1);
key_released = key_pressed;
gfx_clear();
if(DrawFlag)
Draw();
/*Big for for simulate a delay*/
for(i = 0; i <= 100000; i++)
;
}else{
x++;
}
}
}
I, am sure that there is a better way for do this , but you know, It's work...