windowtest.m

#import <Cocoa/Cocoa.h>

@interface MyController : NSObject
- (void)applicationDidFinishLaunching:(NSNotification *)aNotification;
@end

@implementation MyController
- (void)applicationDidFinishLaunching:(NSNotification *)aNotification
{
  NSUInteger winStyle = (NSTitledWindowMask | NSClosableWindowMask
      | NSMiniaturizableWindowMask);

  NSRect contentRect;
  contentRect.size.width = 1024;
  contentRect.size.height = 768;
  contentRect.origin = NSZeroPoint;

  NSWindow* window = [[NSWindow alloc] initWithContentRect:contentRect
                                                 styleMask:winStyle
                                                   backing:NSBackingStoreBuffered
                                                     defer:YES];

  [window makeKeyAndOrderFront:nil];
}
@end

int main(int argc, char **argv) {
  id controller = [[MyController alloc] init];
  id application = [NSApplication sharedApplication];
  [application setDelegate:controller];
  [application run];
  return 0;
}