refresh_rate.m

refresh_rate.m

// gcc refresh_rate.m -framework Cocoa -framework CoreVideo && ./a.out
//
// Prints the refresh rate of your main screen...I think.

#import <Cocoa/Cocoa.h>
#import <Carbon/Carbon.h>

int main() {
    NSScreen *screen = [NSScreen mainScreen];
    CGDirectDisplayID id = (CGDirectDisplayID)[
        [screen deviceDescription][@"NSScreenNumber"] intValue];

    CVDisplayLinkRef link = NULL;
    if (CVDisplayLinkCreateWithCGDisplay(id,  &link) != 0) {
        printf("failed to create display link");
        return 1;
    }

    CVTime time = CVDisplayLinkGetNominalOutputVideoRefreshPeriod(link);
    CVDisplayLinkRelease(link);

    if (!(time.flags & kCVTimeIsIndefinite)) {
        printf(
            "%f (%i / %lld)\n",
            (float)time.timeScale / (float)time.timeValue,
            time.timeScale,
            time.timeValue);
    } else {
        printf("kCVTimeIsIndefinite");
    }

    return 0;
}