[OT] Casting malloc() results (was Re: [Wrapper-user] Mac OS X - Segmentation Fault)

[Joseph K. <joe...@tr...>]

Mike Castle wrote:

> However, I'd like to suggest one change:
> 
> --- src/c/wrapper_unix.c        3 Apr 2003 08:10:19 -0000       1.33
> +++ src/c/wrapper_unix.c        15 Apr 2003 22:11:13 -0000
> @@ -213,8 +213,8 @@
>      /*                        number of arguments + 1 for a NULL pointer
> at the end */
>      for (i = 0; i <= length; i++) {
>          if (i < length) {
> -            wrapperData->jvmCommand[i] = (char *)malloc(sizeof(char *) * strlen(strings[i]) + 1);
> -            sprintf(wrapperData->jvmCommand[i], strings[i]);
> +            wrapperData->jvmCommand[i] = malloc(sizeof(char *) * strlen(strings[i]) + 1);
> +            strcpy(wrapperData->jvmCommand[i], strings[i]);
>          } else {
>              wrapperData->jvmCommand[i] = NULL;
>          }
> 
> First:  in _C_, one should _NEVER_ cast the return value of malloc().  If
> you get warnings without it, your ether your code or compiler is broken.

Hi Mike,

Could you possibly provide a reference for this rule? I have always
cast the results of malloc(), based on the advice contained in
K&R 2nd ed. pg. 142 (K&R2 claims to cover ANSI C), but (obviously)
I haven't done much C programming recently :-)  Other sources I've
looked at say that it's not *necessary* to cast malloc's result,
but that it doesn't hurt. So I'm just wondering about your statement
above, which seems to be made with great conviction :-) Does the
ISO C standard recommend against casting?

[Incidentally, I don't want to start a huge thread about this;
but Leif's response seemed to indicate the answer might be of
general interest, which is why I posted to the list rather than
to Mike directly. If anyone wants to argue about the issue, we can
take it to comp.lang.c.]

Thanks,

-- Joe Knapka