NetNews Offline 2/NetNews Offline Volume 2.iso/news/comp/lang/c-part1/3268

Internet Message Format | 1996-08-05 | 1.7 KB

Path: Rezonet.net!news
From: [e-mail] (Ray Dunn)
Newsgroups: comp.lang.c
Subject: Re: Please help ?!
Date: 25 Jan 1996 00:11:58 GMT
Organization: Ultimate Technographics Inc.
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In referenced article, John R Buchan says...
>>   cpy = (char *) malloc(MAXLEN);
>
>The cast is unnecessary and can hide errors.  You should remove it.

This is the second time I've seen this advice in the last five minutes
in the newsgroup.

Certainly the cast is unnecessary, and certainly *some* unnecessary
casts can hide errors, but casting the result of malloc can *never*
hide an error, because it's telling the compiler to do something it
would do anyway.

On the other hand, if by any chance "cpy" is not a "char *", but you
thought it was when you wrote the statement, then including the cast
will *catch* an error.

I'd go as far as to say that if the argument of malloc, calloc,
etc. contains a sizeof operator such that a number of elements of that
type are being allocated, then adding a cast to a pointer of the same
type to the malloc return is the *safest* thing you can do:

  fred = malloc(n * sizeof(int));

Oops - fred isn't an "int *" it's a "long *", but the compiler wont
issue any warnings, but in:

  fred = (int *)malloc(n * sizeof(int));

the compiler will issue an error.

--
Ray Dunn (opinions are my own) | Phone: [phone]
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