I encounter this problem all the time, when I want to call a function in a while loop but only have it execute once. I always do something like this:

Code:

---

 

var sound_played = 0;

function play_my_sound()
{
     if(sound_played == on) { return; }
     sound_played = on; // when it tries to run the second time, it will return

     ...
}

...
while(whatever)
{
     play_my_sound();
     ...
     wait(1);
}
sound_played = 0; // when the loop is over, reset the variable

 

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Hope that helps.