Re: free() is useless...

Jens.Toerring_at_physik.fu-berlin.de
Date: 09/03/04 

Date: 2 Sep 2004 23:30:38 GMT

Matthew Fisher <matthew@dynamic-memory.com> wrote:
> matt@crazylogic.net (Matt Gostick) wrote in message news:<c4b8d048.0409012204.7f69fc70@posting.google.com>...
>> Well, it's not useless, it just doesn't seem to be working for me.
>>
>> Basically, when I'm returning a pointer from a function, free does not
>> seem to be freeing the memory for me. Here is an example of what I am
>> trying to do:
>>
>> char *blah (void) {
>> char *string;
>>
>> string = (char *) malloc(sizeof("foobar")*sizeof(char));

> The above line has a bug in that the buffer is one byte too short.

>> strcpy(string, "foobar");

Sorry, but the sizeof operator is applied here to a literal string
and that, if I am not completely mistaken, includes the trailing
'\0'. Of course, if the OP would have used strlen() instead it
would be a different story.

> You are lucky however since malloc generally returns a minimum of 8
> bytes.

If the problem would exist he might have been lucky because of that,
but there's no guarantee that all malloc() implementations allocate
at least 8 chars.

> Contradicting some other posters, you should cast.

Would you care to tell why?
                                  Regards, Jens 

-- 
  \   Jens Thoms Toerring  ___  Jens.Toerring@physik.fu-berlin.de
   \__________________________  http://www.toerring.de

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