Roberto Rocco Angeloni

ObjectiveC on Ubuntu Linux 12.04

[Updated on 8th May 2012]

Hi,
as I'm about to become an iPhone programmer (another one?), I've decided to set up an objective-c environment on my Ubuntu too.

First, I've installed the following packages:

sudo apt-get install gnustep-devel gnustep-make libgnustep-base-dev

Second, I've tried to compile a classical Hello World file with gcc. Here's the code ('Ciao mondo' stands for 'Hello world' in Italian):

#import <Foundation/Foundation.h>
int main(int argc, char* argv[]) {
        NSLog(@"Ciao mondo");
        return 0;
}

and i saved the source in a file called main.m

After that I've tried: gcc main.c -o hello and I soon got the following error message:

main.m:2:34: error: Foundation/Foundation.h: No such file or directory
main.m: In function ‘main’:
main.m:5: error: cannot find interface declaration for ‘NXConstantString’

 

So after surfing a while on Yahoo's search results, I came to the solution:

1. Execute

. /usr/share/GNUstep/Makefiles/GNUstep.sh

to initialize the environment variables for the GNUstep.

2. Use the gnustep-config --objc-flags to retrieve the correct flags for gcc and link the main.m with the gnustep-base library, this way:

clang `gnustep-config --objc-flags` -v main.m -lgnustep-base -o hello

3. Execute ./hello and you'll got:

2012-05-08 11:25:30.308 a.out[14082] Ciao mondo

See also:
• Writing GNUstep makefiles and
• Additional Installation on GNUstep.org

 

If you prefere, you can use CLang too the same way:

  clang `gnustep-config --objc-flags` -v main.m -lgnustep-base -o hello

Enjoy,
Rob.