Objective-C program to retrieve screen resolution

screen-size.m

#import <stdio.h>
#import <AppKit/AppKit.h>

/* Compilation: clang -framework AppKit -o screen-size -arch x86_64 -arch arm64 main.m */

/* The main issue is that when run from the command line, there is no window
 * context, so AppKit doesn't know what the active window is, and thus
 * doesn't know what the "main screen" is, so I think it always returns the
 * first one. Is there a way to get the window that launched the process
 * and return the screen it is on?
 */


int main(int argc, char **argv)
{
    int ec = 0;
    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];

    NSSize size = [[NSScreen mainScreen] frame].size;

    printf("%ldx%ld\n", (long) size.width, (long) size.height);

quit:
    [pool release];
    return ec;
}