Name:         grglun

Purpose:      get a Fortran logical unit number (Sun/Convex-UNIX)

Category:     GRAPHICS

File:         pgplot.src

Author:       T.J. Pearson

Use:          see description below.

Description:

            SUBROUTINE GRGLUN(LUN)
            INTEGER LUN
      
       Get an unused Fortran logical unit number. 
       Returns a Logical Unit Number that is not currently opened.
       After GRGLUN is called, the unit should be opened to reserve
       the unit number for future calls.  Once a unit is closed, it
       becomes free and another call to GRGLUN could return the same
       number.  Also, GRGLUN will not return a number in the range 1-9
       as older software will often use these units without warning.
      
       Arguments:
        LUN    : receives the logical unit number, or -1 on error.

Updates:      Oct 16, 1998: JPT automatically extracted from source.