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From: hoover@cs.UAlberta.CA (Jim Hoover)
Newsgroups: comp.lang.perl
Subject: Yet another perl portability bug
Message-ID: <1990Dec11.052604.21319@cs.UAlberta.CA>
Date: 11 Dec 90 05:26:04 GMT
Sender: news@cs.UAlberta.CA (News Administrator)
Organization: University of Alberta, Edmonton, Canada
Lines: 33

Larry:

On my SCO box, perl failed the lib.big test for big integers.  In tracking
down the failure I discovered a bug in the implementation of cmp or of
str_cmp (take your pick).

The cmp operator implementation assumes that str_cmp (in str.c) returns 
one of -1 0 +1. 

str_cmp is implemented with memcmp, which is specified (on my SCO box)
only to return a negative, zero, or positive value.  It says nothing about
the range of values.  SCO's version returns various postive and negative
values.

		Jim Hoover
Here is my fix to str_cmp:

741c741,742
< 	    return retval;
---
> 	    /* FIX - memcmp is not guaranteed to return -1 0 +1, just sign */
> 	    return (retval > 0) ? +1 : -1;
746c747,748
< 	return retval;
---
> 	    /* FIX - memcmp is not guaranteed to return -1 0 +1, just sign */
> 	    return (retval > 0) ? +1 : -1;

--
Prof. Jim Hoover                   | Office +1 403 492 5401 or 5290
Dept. of Computing Science         | FAX    +1 403 492 1071
University of Alberta              | hoover@cs.ualberta.ca
Edmonton, Alberta, Canada T6G 2H1  |