Compiler warnings in gmxcpp.c
chdir() calls in gmxcpp.c trigger compiler warnings at least with gcc 4.3.3:
src/gmxlib/gmxcpp.c: In function ‘cpp_open_file’:
src/gmxlib/gmxcpp.c|200| warning: ignoring return value of ‘chdir’, declared with attribute warn_unused_result
src/gmxlib/gmxcpp.c: In function ‘cpp_close_file’:
src/gmxlib/gmxcpp.c|450| warning: ignoring return value of ‘chdir’, declared with attribute warn_unused_result
Although only a minor annoyance, it should still be worth fixing. Checking for errors in the return value should be straightforward, the only question being how to return from the preprocessor if an error occurs.