maplun(3F)

NAME
     maplun - returns the integer file descriptor for a Fortran logical
     unit number

SYNOPSIS
     maplun (lun)
     integer*4 lun

IMPLEMENTATION
     IRIX systems

     MIPSpro Fortran 77

DESCRIPTION
     This intrinsic function returns the file descriptor given a Fortran
     logical unit number.

     Success is indicated by a non-negative return value.  A negative
     return value indicates an error.  The value of errno can be examined
     to determine the cause of the error.

NOTES
     This function cannot be used on indexed files because each Fortran
     indexed file is represented by two physical files and this function
     cannot map a single Fortran logical unit to two file descriptors.
     Also, the indexed file internal format is proprietary and cannot be
     modified by the user directly; therefore, this function, or a similar
     function, will not help in that respect.

SEE ALSO
     This man page is available only online.