GNUstep under Ubuntu Linux

Objective-C under Ubuntu Linux

Objective-C under Ubuntu Linux

Compiling Everything from Scratch (Ubuntu 14.04, 15.04)

The following script compiles and installs everything needed for Objective-C 2.0 from scratch. The script uses clang and libobjc2 for all the awesome new features like ARC, blocks, etc.

(See below for Ubuntu 12.04 help.)

#!/bin/bash

sudo apt-get update
sudo apt-get -y install build-essential git subversion ninja cmake libffi-dev libxml2-dev \
libgnutls-dev libicu-dev libblocksruntime-dev libkqueue-dev libpthread-workqueue-dev autoconf libtool \
libjpeg-dev libtiff-dev libffi-dev libcairo-dev libx11-dev:i386 libxt-dev libXft-dev

cd ~
git clone git://github.com/nickhutchinson/libdispatch.git
svn co http://svn.gna.org/svn/gnustep/modules/core
git clone https://github.com/gnustep/libobjc2

# OBTAIN, COMPILE, INSTALL THE LATEST LLVM/clang. (Doing apt-get install clang instead may or may not work.)
svn co http://llvm.org/svn/llvm-project/llvm/trunk llvm
cd llvm/tools
svn co http://llvm.org/svn/llvm-project/cfe/trunk clang
cd ~/llvm
rm -rf build
mkdir build
cd build
cmake ..
make -j8   # 8=your number of build CPUs
echo "export PATH=\$PATH:~/llvm/build/bin" >> ~/.bashrc
echo "export CC=clang"  >> ~/.bashrc
echo "export CXX=clang++" >> ~/.bashrc
export PATH=$PATH:~/llvm/build/bin
. ~/.bashrc

export CC=clang
export CXX=clang++

clang -v
clang++ -v

cd ~/libobjc2
rm -rf build
mkdir build
cd build
cmake ..
make -j8
sudo -E make install

cd ~/core/make
./configure --enable-debug-by-default --with-layout=gnustep --enable-objc-nonfragile-abi
make && sudo -E make install
echo ". /usr/GNUstep/System/Library/Makefiles/GNUstep.sh" >> ~/.bashrc

. /usr/GNUstep/System/Library/Makefiles/GNUstep.sh

sudo /sbin/ldconfig

cd ~/core/base/
./configure
make -j8
sudo -E make install

cd ~/libdispatch
rm -rf libdispatch-build
mkdir libdispatch-build && cd libdispatch-build
../configure
make
sudo make install
sudo ldconfig

cd ~/core/gui
./configure
make -j8
sudo -E make install

cd ~/core/back
./configure
make -j8
sudo -E make install

echo "Install is done. Open a new terminal or type source ~/.bashrc"

Test Code

The following is some Objective-C source code from the internet. It demonstrates blocks, Grand Central Dispatch, and the use of GNUStep GUI.

cat > blocktest.m << EOF
#include <stdio.h>

int main() {
    void (^hello)(void) = ^(void) {
        printf("Hello, block!\n");
    };
    hello();
    return 0;
}
EOF

cat > helloGCD_objc.m << EOF

#include <dispatch/dispatch.h>
#import <stdio.h>
#import "Fraction.h"

int main( int argc, const char *argv[] ) {
   dispatch_queue_t queue = dispatch_queue_create(NULL, NULL);
   Fraction *frac = [[Fraction alloc] init];

   [frac setNumerator: 1];
   [frac setDenominator: 3];

   // print it
   dispatch_sync(queue, ^{
     printf( "The fraction is: " );
     [frac print];
     printf( "\n" );
   });
   dispatch_release(queue);

   return 0;
}

EOF

cat > Fraction.h << EOF

#import <Foundation/NSObject.h>

@interface Fraction: NSObject {
   int numerator;
   int denominator;
}

-(void) print;
-(void) setNumerator: (int) n;
-(void) setDenominator: (int) d;
-(int) numerator;
-(int) denominator;
@end

EOF


cat > Fraction.m << EOF
#import "Fraction.h"
#import <stdio.h>

@implementation Fraction
-(void) print {
   printf( "%i/%i", numerator, denominator );
}

-(void) setNumerator: (int) n {
   numerator = n;
}

-(void) setDenominator: (int) d {
   denominator = d;
}

-(int) denominator {
   return denominator;
}

-(int) numerator {
   return numerator;
}
@end

EOF



cat > guitest.m << EOF
#import <AppKit/AppKit.h>

int main()
{
  NSApplication *app;  // Without these 2 lines, seg fault may occur
  app = [NSApplication sharedApplication];

  NSAlert * alert = [[NSAlert alloc] init];
  [alert setMessageText:@"Hello alert"];
  [alert addButtonWithTitle:@"All done"];
  int result = [alert runModal];
  if (result == NSAlertFirstButtonReturn) {
    NSLog(@"First button pressed");
  }
}
EOF

# ======================================================================
# COMPILE USING THE FOLLOWING COMMAND LINES, OR CREATE A MAKEFILE
# ======================================================================

# Using COMMAND LINE

clang `gnustep-config --objc-flags` `gnustep-config --objc-libs` -fobjc-runtime=gnustep -fblocks -fobjc-arc -lobjc  blocktest.m

clang `gnustep-config --objc-flags` `gnustep-config --objc-libs` -fobjc-runtime=gnustep -fblocks -lobjc -ldispatch -lgnustep-base  Fraction.m helloGCD_objc.m

clang `gnustep-config --objc-flags` `gnustep-config --objc-libs`  -fobjc-runtime=gnustep -fblocks -lobjc -fobjc-arc -ldispatch -lgnustep-base -lgnustep-gui  guitest.m

# Using MAKEFILE

cat > GNUmakefile << EOF
include \$(GNUSTEP_MAKEFILES)/common.make

APP_NAME = GUITest
GUITest_OBJC_FILES = guitest.m

include \$(GNUSTEP_MAKEFILES)/application.make
EOF

make
openapp ./GUITest.app

General Note: When compiling your own code, it is generally good to tell clang both the family and version of the runtime: -fobjc-runtime=gnustep-1.8.1 (The current version number can be had by looking at the latest ANNOUNCE filename in https://github.com/gnustep/libobjc2 (e.g., ANNOUNCE.1.8.1))

Ubuntu 12.04 Help

On Ubuntu 12.04, the default installed version of CMake is 2.8.7 but you need 2.8.8 or later to compile LLVM. And the default installed version of GCC and G++ is 4.6 but you need 4.8 or later to compile LLVM.

For CMake, the solution is to download and compile CMake yourself. Use the existing CMake 2.8.7 and then replace it:

1. Download the latest CMake version from the CMake web site (http://www.cmake.org/cmake/resources/software.html), and uncompress it in a folder.
2. Create a _build directory in the CMake sources folder.
3. From the _build directory, run the following commands to build and install CMake from sources:

cmake .. -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/usr
make
cpack -G DEB
sudo apt-get remove cmake cmake-data
sudo dpkg -i cmake*.deb

To get GCC and G++ 4.8, do the following:

sudo add-apt-repository ppa:ubuntu-toolchain-r/test
sudo apt-get update
sudo apt-get install gcc-4.8 g++-4.8
sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-4.8 50
sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-4.8 50

You should be good to go.