Compiler driver / backend version mismatch

[ejs236]

Hello all,
I am using the Intel Fortran compiler and getting the following error when I try to use Ifort

Compiler driver / backend version mismatch: unset != 810
Be sure compiler driver and backend programs are in the same directory.

Both ifort and fortcom are the same version (8.1), they are both in the same directory, and they both have the same date. The user who reported this said that it functioned fine just an hour before. Any ideas why this would suddenly stop working?

Thanks for the help,
Ed Smiley

[TimP]

Are you certain that you don't have multiple compiler versions installed? Even in that case, you should have no problem when ifort and its libraries are accessed via correctly set environment variables. That is, the ifort version you want comes first in PATH and LD_LIBRARY_PATH, as will happen when you set the environment by the script included with the compiler. The common problem is that people will use a fixed path to some particular version somewhere in their build, and it doesn't adjust to use of another version.

[ejs236]

Hi Tim,
Thanks for the prompt response. I now have two versions installed. I have version 8.0 installed in /opt/intel_fce_80 and version 9.0 installed in /opt/intel/fce/9.0. I have edited the path so when I type ifort and fortcom that they both respond with the 9.0 directory. I still get the mismatch. Is there a simple way to have both compilers installed and have the abililty to use both?

Thanks again for your help,
Ed

[TimP]

The compilers are installed in separate directories, by default, as you have done. You should be able to switch between them by the use of PATH and LD_LIBRARY_PATH environment, as the corresponding ifortvars.sh/ifortvars.csh scripts do. Many people have fixed paths buried in Makefile, which bypass environment variables, and that could cause the problem you observe. You might also try removing a compiler installation with the /bin/uninstall.sh script, and make a clean installation, to make sure that the various compiler components belong together.

[ejs236]

Hi Tim,
Thanks again for the quick response. I have uninstalled the 9.0 version and now 8.0 works. How should I go about doing a clean installation? The original 9.0 install was done with all defaults and I do not know how I would do it any differently to get different results.

Thanks again,
Ed

[TimP]

I don't know any reason to suggest a change. I simply wanted to suggest you make sure that everything in the new installation director comes from the same compiler version.