Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!ut-emx!reeder
From: reeder@ut-emx.UUCP (William P. Reeder)
Newsgroups: comp.lang.fortran
Subject: length of a character string
Keywords: null string,  intrinsic function LEN
Message-ID: <18585@ut-emx.UUCP>
Date: 19 Sep 89 16:14:44 GMT
Organization: University of Texas Computation Center
Lines: 37

I was porting NCAR Graphics (version 2.01) to an Alliant yesterday when
I got a compilation error on the third line of the following code
fragment:

	character*80 ncarg
	call getenv('NCARGLIB', ncarg)
	if (ncarg.eq."") then

A quick look in the standard confirmed that a character constant must
contain one or more characters between the apostrophies.  Yes, I know
that those are quotes up there; NCAR must be assuming that all compilers
allow quotes in place of apostrophies in addition to assuming that
everyone allows null strings and lower case letters.

Anyway, I need to check for a null string in variable "ncarg".  I thought
about using the intrinsic function LEN, but that just told me the
size of the character variable (80), not the length of the string stored
there (which may be less than 80).  Is this the proper behavior for LEN?
I can see where you would want to know how much storage was available
in a character variable, but I want to know the length of a string stored
in that variable much more frequently.  I didn't see any standard
intrinsic function defined which might give me this information.

The best idea I have come up with so far for creating a "null" string
is this:

	character*80 null
	write ( null, * )

Does anyone have any better ideas?
-- 
William "Wills" Reeder, The University of Texas at Austin, Computation Center
reeder@emx.utexas.edu, uunet!cs.utexas.edu!ut-emx!reeder, (512)471-3241

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