/sys$common/syshlp/helplib.hlb CC, Run-time functions, lseek  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  Positions a file to an arbitrary byte position and returns the new
  position as an int.

  Syntax:

       #include <unistd.h>

       off_t lseek(int file_descriptor, off_t offset, int direction);