VMS Help CC, Run-time functions, decc$record_read  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  Provides additional flexibility in manipulating and observing RMS
  structures on a per-read basis.  This function is inherently
  specific to OpenVMS systems and should not be used when writing
  portable applications.

  Syntax:

       #include <stdio.h>

       int decc$record_read(FILE *fp, void *buffer, int nbytes);