SDL.framework: How do I use it?

Hey,

I wanted to build this little example SDL program:

http://friedspace.com/SDLTest.c

I saved this a file called sdl.c. On my GNU/Linux box I had no trouble. This,

GNU/Linux$ gcc -I/usr/include/SDL -L/usr/lib sdl.c -lSDL

produces a viable executable. On OS X there are these framework things. I don't know much about them, but they appear to contain all of what is necessary to compile and link a program against, say, SDL. So I installed the SDL framework from http://www.libsdl.org/download-1.2.php (I just copied SDL.framework into /Library/Frameworks) and tried to build the same sample program via:

smithzv@belial:[0]:~/src/work/sdl-examples$ gcc sdl.c -framework SDL
sdl.c:3:16: error: SDL.h: No such file or directory
sdl.c:10: error: parse error before '*' token
sdl.c: In function 'setpixel':
sdl.c:12: error: 'Uint32' undeclared (first use in this function)
sdl.c:12: error: (Each undeclared identifier is reported only once
sdl.c:12: error: for each function it appears in.)
sdl.c:12: error: 'pixmem32' undeclared (first use in this function)
sdl.c:13: error: parse error before 'colour'
sdl.c:15: error: 'colour' undeclared (first use in this function)
sdl.c:15: error: 'screen' undeclared (first use in this function)
sdl.c:15: error: 'r' undeclared (first use in this function)
sdl.c:15: error: 'g' undeclared (first use in this function)
sdl.c:15: error: 'b' undeclared (first use in this function)
sdl.c:17: error: parse error before ')' token
sdl.c: At top level:
sdl.c:22: error: parse error before '*' token
sdl.c: In function 'DrawScreen':
sdl.c:26: error: 'screen' undeclared (first use in this function)
sdl.c:36: error: 'h' undeclared (first use in this function)
sdl.c: In function 'main':
sdl.c:48: error: 'SDL_Surface' undeclared (first use in this function)
sdl.c:48: error: 'screen' undeclared (first use in this function)
sdl.c:49: error: 'SDL_Event' undeclared (first use in this function)
sdl.c:49: error: parse error before 'event'
sdl.c:54: error: 'SDL_INIT_VIDEO' undeclared (first use in this function)
sdl.c:56: error: 'SDL_FULLSCREEN' undeclared (first use in this function)
sdl.c:56: error: 'SDL_HWSURFACE' undeclared (first use in this function)
sdl.c:65: error: 'event' undeclared (first use in this function)
sdl.c:69: error: 'SDL_QUIT' undeclared (first use in this function)
sdl.c:72: error: 'SDL_KEYDOWN' undeclared (first use in this function)

Okay, it cannot find the header files. I tried adding a -F/Library/Frameworks to the options but it made no difference. I tried explicitly compiling and the linking passing the framework option to the linker by hand:

smithzv@belial:[0]:~/src/work/sdl-examples$ gcc -c sdl.c -I/Library/Frameworks/SDL.framework/Headers
smithzv@belial:[0]:~/src/work/sdl-examples$ ld -framework SDL sdl.o
ld: /Library/Frameworks/SDL.framework/SDL load command 6 unknown cmd field

...still no go. I also thought that maybe I could get around the frameworks if I installed SDL through MacPorts, which I did. So I tried this (my MacPorts tree is in the default /opt/local):

smithzv@belial:[0]:~/src/work/sdl-examples$ gcc -c sdl.c -I/opt/local/include/SDL
smithzv@belial:[0]:~/src/work/sdl-examples$ gcc sdl.o -L/opt/local/lib -lSDL
/usr/bin/ld: Undefined symbols:
_main
collect2: ld returned 1 exit status

Hmmm... okay, let's check...

smithzv@belial:[0]:~/src/work/sdl-examples$ nm sdl.o
0000006c T _DrawScreen
U _SDL_Flip
U _SDL_Init
U _SDL_LockSurface
U _SDL_MapRGB
U _SDL_PollEvent
U _SDL_Quit
U _SDL_SetVideoMode
U _SDL_UnlockSurface
000001cb T _SDL_main
00000000 T _setpixel

...sure enough, no main symbol. For comparison, on the linux box...

GNU/Linux$ nm sdl.o
0000006f T DrawScreen
U SDL_Flip
U SDL_Init
U SDL_LockSurface
U SDL_MapRGB
U SDL_PollEvent
U SDL_Quit
U SDL_SetVideoMode
U SDL_UnlockSurface
000001cc T main
00000000 T setpixel

...we do get a main function.

Any thoughts on what I am doing wrong? I have reinstalled the SDL framework, but this had no effect.

Thanks for any hints,
Zach

BTW I have had a hard time finding much help on developing in OS X. If anyone has some links, I would love to check them out.

Welcome to Linux Questions

sdl.c:3:16: error: SDL.h: No such file or directory

Well so far only 1 error !
But you need to install package "sdl-1.2.x"
It is on install disc 2 /l (l for libraries (L))
or get it from "getslack" e.g.
ftp://ftp.heanet.ie/mirrors/ftp.slac...pub/slackware/

Copying files from the source code to a directory
will not do.

Regards

P.S.: Slackware packages are to be installed with
the command # 'installpkg <package.tgz>'

Well so far only 1 error ! But you need to install package "sdl-1.2.x" It is on install disc 2 /l (l for libraries (L)) or get it from "getslack" e.g. ftp://ftp.heanet.ie/mirrors/ftp.slac...pub/slackware/

Oh, sorry, there must be some misunderstanding (maybe on my part). On GNU/Linux (in fact, my Slackware box) this does work exactly as I expect. I am having a problem on OS X. I though that providing information ensuring that the program compiles and works fine elsewhere might help in trouble shooting this problem. I guess this caused more confusion than clarification.

On Mac OS X 10.4 (distributed by Apple Computers) I cannot use the thing Apple calls the SDL framework.

Copying files from the source code to a directory will not do.

In the README for installation:

To Install: Copy the SDL.framework to /Library/Frameworks

As is commonly the case with OS X software, installation requires copying a directory to a special location. This directory contains all relevant code like the header files and the shared libraries. This is a bit different from the standard "all headers in /usr/include, all libraries in /usr/lib" method of other *NIX operating systems

However, if you want to work from something that looks more like GNU/Linux, I have the SDL library installed in such a way. In this case, I get this kind of behavior (from the original post)...

smithzv@belial:[0]:~/src/work/sdl-examples$ gcc -c sdl.c -I/opt/local/include/SDL smithzv@belial:[0]:~/src/work/sdl-examples$ gcc sdl.o -L/opt/local/lib -lSDL /usr/bin/ld: Undefined symbols: _main collect2: ld returned 1 exit status

But, to be honest, I have no idea what kind of tom foolery OS X or Apple's version of gcc might be pulling in the background, nor do I have any verification that the library built and installed correctly (only that an error was not encountered during the build).

Thanks,
Zach

Okay,

I have a solution, though it is not ideal (i.e. I still do not know how to use the SDL framework). One issue is that I was not including the flag -lSDLmain for the linker. I guess this isn't necessary for the GNU/Linux build. In fact it seems that on the Slackware box libSDLmain doesn't to much at all, but on OS X it adds a bunch of Cocoa stuff. The lack of -lSDLmain explains the missing symbol on OS X.

After adding -lSDLmain, I get more undefined symbols. These are from Cocoa.

smithzv@belial:[0]:~/src/work/sdl-examples$ gcc sdl.c -I/opt/local/include/SDL -L/opt/local/lib -lSDLmain -lSDL 
/usr/bin/ld: Undefined symbols:
.objc_class_name_NSApplication
.objc_class_name_NSAutoreleasePool
.objc_class_name_NSMenu
.objc_class_name_NSMenuItem
.objc_class_name_NSObject
.objc_class_name_NSProcessInfo
.objc_class_name_NSString
_CFBundleCopyBundleURL
_CFBundleGetInfoDictionary
_CFBundleGetMainBundle
_CFRelease
_CFURLCreateCopyDeletingLastPathComponent
_CFURLGetFileSystemRepresentation
_CPSEnableForegroundOperation
_CPSGetCurrentProcess
_CPSSetFrontProcess
_NSAllocateMemoryPages
_NSApp
_NSDeallocateMemoryPages
___CFConstantStringClassReference
_objc_msgSend
collect2: ld returned 1 exit status

So I need to add a -framework Cocoa in order to resolve them. Problem solved, except I am still using the MacPorts version of SDL, not the framework in /Library/Frameworks. But I guess the Cocoa framework worked as expected. Maybe I am using them right and there is something wrong with the SDL distribution.

Well, I guess this will work well enough for now,
Zach

Did you try this:
http://gpwiki.org/index.php/C:How_to...MacOS_X:_Xcode

Did you try this: http://gpwiki.org/index.php/C:How_to...MacOS_X:_Xcode

Looks like I need some RTFM over here.

I have little desire to touch ProjectBuilder/Xcode. For the most part, I really want to use OS X as if it were a Linux box. That way what I write on it will run at home. So this exact section isn't so much help, but later on a link caught my eye which lead me to the OS X FAQ for SDL. Embarrassingly enough, this answered almost all of my questions, which I guess must therefore be frequently asked. I know how unresearched threads like this can be annoying, so I will apologize to the readers out there.

Anyway, in case someone else is searching on this, here is the FAQ page:

http://www.libsdl.org/faq.php?action...ies&category=7

Basically, linking against SDL.framework is only for Project Builder/Xcode stuff, not for C programs like the one I was building. The FAQ does hint that some C/C++ projects (I know not which) that do link against SDL.framework, but it suggests that it takes some trickery. It looks like the solution I finally stumbled upon is the suggested solution for SDL on OS X in C/C++.

Zach

Hi Zach,

I've been trying to figure this out for the past 2 days as well. Your link has been moved. Can you shine any light on this?

I would like to use the framework to link to my .o files. It seems to work now with the SDL framework:

all: main.o
g++ -g -Wall main.o -lSDLmain -framework Cocoa -framework SDL
main.o: main.cpp
g++ -g -c -Wall main.cpp
clean:
rm -f *.o
rm -f a.out

But when I try to add the SDL_image framework, I receive the following:

g++ -g -Wall main.o -lSDLmain -framework Cocoa -framework SDL -framework


/Library/Frameworks/SDL_image.framework/Headers/SDL_image.h:28:17: error: SDL.h: No such file or directory
/Library/Frameworks/SDL_image.framework/Headers/SDL_image.h:29:25: error: SDL_version.h: No such file or directory
/Library/Frameworks/SDL_image.framework/Headers/SDL_image.h:30:24: error: begin_code.h: No such file or directory
/Library/Frameworks/SDL_image.framework/Headers/SDL_image.h:134:24: error: close_code.h: No such file or directory

I can see that the SDL.h header does exist in the SDL.framework, so I try to include it with -I/Library/Frameworks/SDL.framework/Headers/. So now I have the following:

g++ -g -Wall main.o -lSDLmain -framework Cocoa -framework SDL -framework -I/Library/Frameworks/SDL.framework/Headers/

But I still receive the same errors:


In file included from main.cpp:11:
/Library/Frameworks/SDL_image.framework/Headers/SDL_image.h:28:17: error: SDL.h: No such file or directory
/Library/Frameworks/SDL_image.framework/Headers/SDL_image.h:29:25: error: SDL_version.h: No such file or directory
/Library/Frameworks/SDL_image.framework/Headers/SDL_image.h:30:24: error: begin_code.h: No such file or directory
/Library/Frameworks/SDL_image.framework/Headers/SDL_image.h:134:24: error: close_code.h: No such file or directory
make: *** [main.o] Error 1

**UPDATE**

Nevermind. I wasn't including the the headers with the -I with .cpp but doing it after my .cpp files were turned into machine code at .o
I'm still learning.

if I disabled letting it wait for a vertical retrace (I assume that's what you meant by Vsync) wouldn't it tear the screen? Also, I do plan on drawing more stuff and doing more processing between flips, the problem is that there is too much time between the flips to get a good frame rate.

This thread is over 3 years old. You are better off starting a new thread so you can get up to date information.

@ myhealth, did you read the LQ rules when you signed up?