Technical Q&A QA1567

Compiling X11 / OpenGL applications on Mac OS X v.10.5 Leopard

Q: At compile time I am getting "ld: cycle in dylib re-exports with /usr/X11R6/lib/libGL.dylib"

How can I properly build my application?

A: While building X11 / OpenGL applications like this:

gcc glxgears.c -o glxgears -I/usr/X11R6/include -L/usr/X11R6/lib -lGL -lX11

Some developers might experience the following error:

ld: cycle in dylib re-exports with /usr/X11R6/lib/libGL.dylib
collect2: ld returned 1 exit status

Background

The linker on Mac OS X v.10.5 searches -L paths for indirect libraries and in doing so it finds two copies of libGL.dylib. One in /usr/X11/lib and the other in /System/Library/Frameworks/OpenGL.framework/Versions/A/Libraries and this causes a cycle.

This is a side effect of various linker improvements in Leopard, which we may be able to mitigate in a future release.

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Workaround

You can overcome this problem by providing the -dylib_file option to the linker. The -dylib_file option is described as:

-dylib_file install_name:file_name
   Specifies that a dynamic shared library is in a different location than its standard location.
   Use this option when you link with a library that is dependent on a dynamic library, and the
   dynamic library is in a location other than its default location. install_name specifies the path
   where the library normally resides. file_name specifies the path of the library you want to use
   instead. For example, if you link to a library that depends upon the dynamic library libsys
   and you have libsys installed in a nondefault location, you would use this option:
   -dylib_file /lib/libsys_s.A.dylib:/me/lib/libsys_s.A.dylib.

For this specific issue the -dyld_file option should be used like this:

-dylib_file \
/System/Library/Frameworks/OpenGL.framework/Versions/A/Libraries/libGL.dylib:\
/System/Library/Frameworks/OpenGL.framework/Versions/A/Libraries/libGL.dylib

A full compile line for an application might look like this:

gcc glxgears.c -o glxgears -I/usr/X11R6/include -L/usr/X11R6/lib -lGL -lX11 -dylib_file \
/System/Library/Frameworks/OpenGL.framework/Versions/A/Libraries/libGL.dylib:\
/System/Library/Frameworks/OpenGL.framework/Versions/A/Libraries/libGL.dylib

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Document Revision History

Posted: 2007-10-30