bproc_requestfile uses the BProc file cache interface to request a file. If successful, bproc_requestfile will return an open file descriptor for the file. The file will be opened in read-only mode.
The file cache is a feature of the slave side in BProc. This call will only work on slave nodes.
On success, bproc_requestfile will return a file descriptor number. On error, it will return -1 and errno will be set appropriately.
bproc_requestfile was called on the front end.
filename is an invalid pointer.
The file cache either failed or refused to fetch filename.
The BProc system is not running.