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From: composer@chem.bu.edu (Jeff Kellem)
Newsgroups: comp.lang.perl
Subject: bug with combination of loops and <glob> mechanism
Message-ID: <COMPOSER.90Sep2031043@chem.bu.edu>
Date: 2 Sep 90 07:10:43 GMT
Sender: root@bu.edu.bu.edu
Reply-To: composer@chem.bu.edu
Organization: Boston University Chemistry Department
Lines: 41

The following short script doesn't work properly in perl compiled with these
configurations:

    perl 3.0 pl18:
	Sun 3, SunOS 4.0.3, cc, yacc
    perl 3.0 pl28:
	Sun 3, SunOS 4.0.3, gcc 1.37.1, bison 1.11
	Encore Multimax, UMAX 4.2, gcc 1.37.1, bison 1.11

The script:

	#!/usr/bin/perl
	#
	while (1) {
	    $dir=<~user>;
	    print "DIR=$dir\n";
	}

prints, assuming `~user' == `/foo/bar',

DIR=/foo/bar
DIR=
DIR=/foo/bar
DIR=
 :
 :

It seems that on every other iteration through the loop, no globbing is done
(i.e. no exec of csh occurs).  If you add a few more copies of the globbing
line `$dir=<~user>;' in the script, you should notice the difference in speed
between printing each line.

Note that this also occurs when combined with other looping mechanisms, such
as `foreach', `LABEL: BLOCK goto LABEL', etc.

Any ideas, Larry?

				-jeff

Jeff Kellem
Internet: composer@chem.bu.edu