[Jackaudio] read jack audio data outside process callback

Hello JACKies, i tinkered this thing https://github.com/oskude/jackplot that plots jack audio data with opengl in real-time (and am a really happy puppy :D). but as i'm a c, jack and opengl noob, i was hoping to get some help here. (at least for the jack part) so i set the jack data (pointer) to a global variable https://github.com/oskude/jackplot/blob/bcac59813b01b3bf7c2ebebd4988b22f5bf… and read that data in opengl draw function (when ever its ready to draw) https://github.com/oskude/jackplot/blob/bcac59813b01b3bf7c2ebebd4988b22f5bf… (ignoring the function i read it in, am i even reading the jack data correctly?) i'm suprised that it works, and hasn't crashed! but i have the feeling that this is a bad/unsafe way to do it... any thoughts? tips? links? Cheers, Andre Osku Schmidt ps. i know about error checking, but i would like to keep this code as small as possible, until i understand the core jack-audio-data-to-opengl-points part.