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From: ltf@ncmicro.lonestar.org (Lance Franklin)
Newsgroups: comp.sys.dec
Subject: Re: strcat(foo,NULL) core dumps on Ultrix
Keywords: dec c strcat
Message-ID: <400@ncmicro.lonestar.org>
Date: 12 Jun 91 17:05:57 GMT
References: <966@sdrc.COM>
Organization: NC Microproducts, Inc. Richardson, Tx
Lines: 35

In article <966@sdrc.COM> wggabb@sdrc.COM (Rob Gabbard) writes:
}A call to strcat with NULL as the second argument core dumps with a memory 
}fault on Ultrix.  Why would anyone want to do this anyway ? How about....
}
}	strcat(foo,getenv("FOO"))
}
}		instead of
}
}	if (getenv("FOO")) strcat(foo,getenv("FOO"));

 Try:   if ((s=getenv("FOO"))) strcat(foo,s);

 Where s is defined as (char *).

}
}Actually, just coding strcat(foo,NULL) will dump.  Anyone run into this ?
}Am I doing a no-no here.

Yup...figure it out, why put up with a lot of overhead on error checking
on string handling routines where 95% of the calls are of the type:

    strcat(foo,"string");

After all, if you check for NULL on strcat, you might as well do it in
all the other str* routines...that's a lot of error checking in a set of
routines you would prefer to be as fast as possible.

Lance


-- 
Lance T. Franklin            +----------------------------------------------+
(ltf@ncmicro.lonestar.org)   | "You want I should bop you with this here    |
NC Microproducts, Inc.       |    Lollipop?!?"                 The Fat Fury |
Richardson, Texas            +----------------------------------------------+