skipping incompatible libGL.so

Question

I have freshly installed Fedora 19 x86_64 on my PC. I wrote a simple OpenGL program, but failed to compile it.

    gcc -o quad quad.c -lX11 -lGL -lGLU
    /usr/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-redhat-linux/4.8.1/../..        /../libGL.so when searching for -lGL
    /usr/bin/ld: skipping incompatible /lib/libGL.so when searching for -lGL
    /usr/bin/ld: skipping incompatible /usr/lib/libGL.so when searching for -lGL
    /usr/bin/ld: cannot find -lGL
    collect2: error: ld returned 1 exit status

I have MesaGL and other libraries in place (i.e. /usr/lib) then what's wrong ?

Answer 1

For me, something was wrong with the library symlinks:

$ locate libGL.so | egrep ^/usr | xargs file
/usr/lib/libGL.so:                     symbolic link to `/usr/lib/libGL.so.1'
/usr/lib/libGL.so.1:                   symbolic link to `/usr/lib/libGL.so.1.2'
/usr/lib/libGL.so.1.2:                 symbolic link to `/usr/lib/fglrx/fglrx-libGL.so.1.2'
/usr/lib/fglrx/fglrx-libGL.so.1.2:     ELF 32-bit LSB shared object, Intel 80386, version 1 (SYSV), dynamically linked, stripped
/usr/lib64/FGL.renamed.libGL.so.1.2.0: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, BuildID[sha1]=46121ec8b16424a8b65a0cf11c3f9730ae0e49f5, stripped
/usr/lib64/libGL.so:                   broken symbolic link to `libGL.so.1.2.0'
/usr/lib64/libGL.so.1:                 symbolic link to `/usr/lib64/libGL.so.1.2'
/usr/lib64/libGL.so.1.2:               symbolic link to `/usr/lib64/fglrx/fglrx-libGL.so.1.2'
/usr/lib64/fglrx/fglrx-libGL.so.1.2:   ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, stripped

So /usr/lib/libGL.so pointed at a 32-bit lib and /usr/lib/libGL.so was a broken link. I fixed the /usr/lib64 version to point correctly at libGL.so.1 (and the /usr/lib version to point at the 64 bit version for good measure) and this seems to have gotten my code compiling.