Creating window application in pure c on mac osx
I did a translation of the accepted answer to Pure C:
// based on https://stackoverflow.com/a/30269562
// Minimal Pure C code to create a window in Cocoa
// $ clang minimal.c -framework Cocoa -o minimal.app
#include <objc/runtime.h>
#include <objc/message.h>
#include <Carbon/Carbon.h>
#define cls objc_getClass
#define sel sel_getUid
#define msg ((id (*)(id, SEL, ...))objc_msgSend)
#define cls_msg ((id (*)(Class, SEL, ...))objc_msgSend)
// poor man's bindings!
typedef enum NSApplicationActivationPolicy {
NSApplicationActivationPolicyRegular = 0,
NSApplicationActivationPolicyAccessory = 1,
NSApplicationActivationPolicyERROR = 2,
} NSApplicationActivationPolicy;
typedef enum NSWindowStyleMask {
NSWindowStyleMaskBorderless = 0,
NSWindowStyleMaskTitled = 1 << 0,
NSWindowStyleMaskClosable = 1 << 1,
NSWindowStyleMaskMiniaturizable = 1 << 2,
NSWindowStyleMaskResizable = 1 << 3,
} NSWindowStyleMask;
typedef enum NSBackingStoreType {
NSBackingStoreBuffered = 2,
} NSBackingStoreType;
int main(int argc, char *argv[])
{
// id app = [NSApplication sharedApplication];
id app = cls_msg(cls("NSApplication"), sel("sharedApplication"));
// [app setActivationPolicy:NSApplicationActivationPolicyRegular];
msg(app, sel("setActivationPolicy:"), NSApplicationActivationPolicyRegular);
struct CGRect frameRect = {0, 0, 600, 500};
// id window = [[NSWindow alloc] initWithContentRect:frameRect styleMask:NSWindowStyleMaskTitled|NSWindowStyleMaskClosable|NSWindowStyleMaskResizable backing:NSBackingStoreBuffered defer:NO];
id window = msg(cls_msg(cls("NSWindow"), sel("alloc")),
sel("initWithContentRect:styleMask:backing:defer:"),
frameRect,
NSWindowStyleMaskTitled|NSWindowStyleMaskClosable|NSWindowStyleMaskResizable,
NSBackingStoreBuffered,
false);
msg(window, sel("setTitle:"), cls_msg(cls("NSString"), sel("stringWithUTF8String:"), "Pure C App"));
// [window makeKeyAndOrderFront:nil];
msg(window, sel("makeKeyAndOrderFront:"), nil);
// [app activateIgnoringOtherApps:YES];
msg(app, sel("activateIgnoringOtherApps:"), true);
msg(app, sel("run"));
}
Can you do this? Yes and no (you can do anything if you're persistent enough). Yes you can, but no you shouldn't. Regardless, this can be done for the incredibly persistent among you. Since coding up an example will take awhile, I found a generous soul on the net who already did it. Look at this repository on GitHub for the full code and explanations. Here are some snippets:
cmacs_simple_msgSend((id)objc_getClass("NSApplication"), sel_getUid("sharedApplication"));
if (NSApp == NULL) {
fprintf(stderr,"Failed to initialized NSApplication... terminating...\n");
return;
}
id appDelObj = cmacs_simple_msgSend((id)objc_getClass("AppDelegate"), sel_getUid("alloc"));
appDelObj = cmacs_simple_msgSend(appDelObj, sel_getUid("init"));
cmacs_void_msgSend1(NSApp, sel_getUid("setDelegate:"), appDelObj);
cmacs_void_msgSend(NSApp, sel_getUid("run"));
As you'll notice, this code uses the Objective-C runtime API to create a faux AppDelegate. And creating the window is an involved process:
self->window = cmacs_simple_msgSend((id)objc_getClass("NSWindow"), sel_getUid("alloc"));
/// Create an instance of the window.
self->window = cmacs_window_init_msgSend(self->window, sel_getUid("initWithContentRect:styleMask:backing:defer:"), (CMRect){0,0,1024,460}, (NSTitledWindowMask | NSClosableWindowMask | NSResizableWindowMask | NSMiniaturizableWindowMask), 0, false);
/// Create an instance of our view class.
///
/// Relies on the view having declared a constructor that allocates a class pair for it.
id view = cmacs_rect_msgSend1(cmacs_simple_msgSend((id)objc_getClass("View"), sel_getUid("alloc")), sel_getUid("initWithFrame:"), (CMRect){ 0, 0, 320, 480 });
// here we simply add the view to the window.
cmacs_void_msgSend1(self->window, sel_getUid("setContentView:"), view);
cmacs_simple_msgSend(self->window, sel_getUid("becomeFirstResponder"));
// Shows our window in the bottom-left hand corner of the screen.
cmacs_void_msgSend1(self->window, sel_getUid("makeKeyAndOrderFront:"), self);
return YES;
So, yes. You can write a Cocoa app in pure C. But I wouldn't recommend it. 90% of that code can be replaced by an xib file, and doing it this way really restricts your app because more advanced features of the Apple development stack really on Objective-C features. While it's technically possible to do everything this way, you're making it much harder than it ought to be.
You can use Objective-C runtime API example (iOS) Creating an iOS app in pure C
Alternative the same code in obj-c :
echo '#import <Cocoa/Cocoa.h>
int main ()
{
@autoreleasepool{
[NSApplication sharedApplication];
[NSApp setActivationPolicy:NSApplicationActivationPolicyRegular];
id applicationName = [[NSProcessInfo processInfo] processName];
id window = [[NSWindow alloc] initWithContentRect:NSMakeRect(0, 0, 120, 120)
styleMask:NSTitledWindowMask backing:NSBackingStoreBuffered defer:NO];
[window cascadeTopLeftFromPoint:NSMakePoint(20,20)];
[window setTitle: applicationName];
[window makeKeyAndOrderFront:nil];
[NSApp activateIgnoringOtherApps:YES];
[NSApp run];
}
return 0;
}' | gcc -fobjc-arc -framework Cocoa -x objective-c -o MicroApp - ; ./MicroApp
This will run Cocoa app with 1 window. Like on screenshot below
You can actually add menu using NSMenu
id applicationMenuBar = [NSMenu new];
id appMenuItem = [NSMenuItem new];
[applicationMenuBar addItem:appMenuItem];
[NSApp setMainMenu: applicationMenuBar];
I remember seeing this question about a year ago, back when I so desperately wished I could open up a d*** window, googling for days and only finding the type of answers you see above this post.
I was reading up on the operating system the Mac is built on - Berkley Software Distribution. http://codex.cs.yale.edu/avi/os-book/OS9/appendices-dir/a.pdf Where on page 17 the phrase "...X Windowing System developed at MIT" hit me and I remembered how I couldn't open up a window and how pissed I was about that, and I thought maybe this was finally the solution!
I googled "BSD X Window Programming" and stumbled my way into finally getting a window open in pure C.
I just discovered it so I'm not a master yet but look at this link https://en.wikibooks.org/wiki/X_Window_Programming/Xlib and go to the example, make sure to follow the comments at the top for how to compile with the X11 library (you can ignore the -Wall and -O commands as long as you have the -lX11).
If you can't compile, if it can't find the header files, you'll need to help it find the header files.
There might be a couple different places that the X11 includes could be on your system. More than likely you'll find it in /opt/X11/include which will have all the definitions of the headers you'll need.
You could include the full path in your C programs such as:
#include "/opt/X11/include/X11/Xlib.h"
But we want it to look like this #include <X11/Xlib.h>
So you could add this switch to GCC when you compile -I /opt/X11/include
Or go to your .profile or .bashrc or .bash_profile in your home directory and add:
export C_INCLUDE_PATH="$C_INCLUDE_PATH:/opt/X11/include"
/*
Simple Xlib application drawing a box in a window.
*/
From the wiki:
#include<X11/Xlib.h>
#include<stdio.h>
#include<stdlib.h> // prevents error for exit on line 18 when compiling with gcc
int main() {
Display *d;
int s;
Window w;
XEvent e;
/* open connection with the server */
d=XOpenDisplay(NULL);
if(d==NULL) {
printf("Cannot open display\n");
exit(1);
}
s=DefaultScreen(d);
/* create window */
w=XCreateSimpleWindow(d, RootWindow(d, s), 10, 10, 100, 100, 1,
BlackPixel(d, s), WhitePixel(d, s));
// Process Window Close Event through event handler so XNextEvent does Not fail
Atom delWindow = XInternAtom( d, "WM_DELETE_WINDOW", 0 );
XSetWMProtocols(d , w, &delWindow, 1);
/* select kind of events we are interested in */
XSelectInput(d, w, ExposureMask | KeyPressMask);
/* map (show) the window */
XMapWindow(d, w);
/* event loop */
while(1) {
XNextEvent(d, &e);
/* draw or redraw the window */
if(e.type==Expose) {
XFillRectangle(d, w, DefaultGC(d, s), 20, 20, 10, 10);
}
/* exit on key press */
if(e.type==KeyPress)
break;
// Handle Windows Close Event
if(e.type==ClientMessage)
break;
}
/* destroy our window */
XDestroyWindow(d, w);
/* close connection to server */
XCloseDisplay(d);
return 0;
}
Compile:
gcc -O2 -Wall -o test test.c -L /usr/X11R6/lib -lX11 -lm