This can improve performance significantly on systems with high disk bandwidth. The environment variables have priority over the info keys. The environment-variables method assumes that the environment variables can be read by each process in the MPI job. You will also need to specify the full path name of the PVFS library. As a result, the size of the library is reduced considerably.
GNU make supports it, for example.
This method works only if the make utility supports virtual paths. Lots of miscellaneous bug fixes and other enhancements. These hints are understood only if supplied at file-creation time. They are useful for accessing arrays stored in files. C, Fortran, and profiling interfaces are provided for all functions that have been implemented.