OpenGL test code doesn't work on mac OS X - macos

Question

This code works on GNU/Linux but I can't find how to make it run on Mac OS X Lion.
Here is a test code. Nothing too hard to understand, only an empty window waiting for a quit event to stop. If I comment the glClear call, everything works fine... in fact glClear or any gl call makes it crash on a nice Segmentation fault.
Here is the code :
#include <iostream>
#include <SDL/SDL.h>
#include <SDL/SDL_opengl.h>
int main( int ac, char **av )
{
SDL_Surface *screen;
SDL_Init( SDL_INIT_VIDEO );
if(SDL_GL_SetAttribute(SDL_GL_RED_SIZE, 8) < 0) { printf("opengl error: %s\n", SDL_GetError()); }
if(SDL_GL_SetAttribute(SDL_GL_BLUE_SIZE, 8) < 0) { printf("opengl error: %s\n", SDL_GetError()); }
if(SDL_GL_SetAttribute(SDL_GL_GREEN_SIZE, 8) < 0) { printf("opengl error: %s\n", SDL_GetError()); }
if(SDL_GL_SetAttribute(SDL_GL_BUFFER_SIZE, 32) < 0) { printf("opengl error: %s\n", SDL_GetError()); }
if(SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1) < 0) { printf("couldn't set double buffering: %s\n", SDL_GetError()); }
if ( (screen = SDL_SetVideoMode( 640, 480, 32, SDL_OPENGL | SDL_NOFRAME | SDL_DOUBLEBUF )) == NULL )
{
exit( EXIT_FAILURE );
}
SDL_WM_SetCaption( "test", NULL );
bool loop = true;
SDL_Event event;
while ( loop )
{
glClear( GL_COLOR_BUFFER_BIT );
SDL_PollEvent( &event );
switch ( event.type )
{
case SDL_QUIT:
loop = false;
break;
}
}
SDL_Quit();
return 0;
}
Here is the how I compile it:
g++ -g -I/opt/local/include -I/usr/X11R6/include -L/opt/local/lib -lSDLmain -lSDL -Wl,-framework,Cocoa -L/usr/X11R6/lib -lGL main.cpp
gdb does not help me so much:
Reason: KERN_INVALID_ADDRESS at address: 0x0000000000000000
0x0000000000000000 in ?? ()
(gdb) bt
#0 0x0000000000000000 in ?? ()
#1 0x000000010000269d in SDL_main (ac=1, av=0x100517c90) at main.cpp:28
#2 0x0000000100002360 in -[SDLMain applicationDidFinishLaunching:] ()
#3 0x00007fff90bc2de2 in __-[NSNotificationCenter addObserver:selector:name:object:]_block_invoke_1 ()
#4 0x00007fff8c354e0a in _CFXNotificationPost ()
#5 0x00007fff90baf097 in -[NSNotificationCenter postNotificationName:object:userInfo:] ()
#6 0x00007fff8a49faa7 in -[NSApplication _postDidFinishNotification] ()
#7 0x00007fff8a49f80d in -[NSApplication _sendFinishLaunchingNotification] ()
#8 0x00007fff8a49e4d2 in -[NSApplication(NSAppleEventHandling) _handleAEOpenEvent:] ()
#9 0x00007fff8a49e233 in -[NSApplication(NSAppleEventHandling) _handleCoreEvent:withReplyEvent:] ()
#10 0x00007fff8c39e851 in -[NSObject performSelector:withObject:withObject:] ()
#11 0x00007fff90be589b in __-[NSAppleEventManager setEventHandler:andSelector:forEventClass:andEventID:]_block_invoke_1 ()
#12 0x00007fff90be4822 in -[NSAppleEventManager dispatchRawAppleEvent:withRawReply:handlerRefCon:] ()
#13 0x00007fff90be46b0 in _NSAppleEventManagerGenericHandler ()
#14 0x00007fff8e760c25 in aeDispatchAppleEvent ()
#15 0x00007fff8e760b03 in dispatchEventAndSendReply ()
#16 0x00007fff8e7609f7 in aeProcessAppleEvent ()
#17 0x00007fff912a1b6d in AEProcessAppleEvent ()
#18 0x00007fff8a49b63d in _DPSNextEvent ()
#19 0x00007fff8a49acf5 in -[NSApplication nextEventMatchingMask:untilDate:inMode:dequeue:] ()
#20 0x00007fff8a49762d in -[NSApplication run] ()
#21 0x0000000100002174 in main ()

Answer 1

I'm not sure, but IIRC you need to add the OpenGL framework as well, if using SDL for window and context creation.