What causes undefined reference errors in gfortran compilation?

[SAks]

Hi friends!
I am a complete newbie to fortran..
I've been trying to compile linpack but keep getting following error..

[SAks@localhost Desktop]$ gfortran schdc.f -lblas
/usr/bin/ld: cannot find -lblas
collect2: ld returned 1 exit status

please advise..

Thanks in advance

 

[jtbell]

It means that the 'blas' library either is not installed, or is not in the location where the compiler (actually the linker) expects to find it.

If that library is in a non-standard location, e.g. /foo/bar/blas.a or /foo/bar/blas.dylib or whatever filename extension your OS uses for libraries, then you can tell the linker to search the directory /foo/bar for libraries, in addition to wherever it already searches:

gfortran schdc.f -L/foo/bar -lblas

You might have to add a slash: -L/foo/bar/ (it's been a long time since I had to do this)

The main thing is to give the full directory path.

 

[SAks]

@jtbell
thanks for responding..
I did give the whole path, now some new problem..
this is what i get..

[SAks@localhost Desktop]$ gfortran schdc.f -L/home/SAks/Desktop -lblas
/usr/lib/gcc/x86_64-redhat-linux/4.4.5/libgfortranbegin.a(fmain.o): In function `main':
(.text+0x26): undefined reference to `MAIN__'
collect2: ld returned 1 exit status