MESSAGE
| DATE | 2005-01-26 |
| FROM | Ruben Safir
|
| SUBJECT | Re: [hangout] Simple C question
|
On Tue, 2005-01-25 at 16:03, Billy wrote:
> Inker, Evan wrote:
> > Check this out
> >
> > strcopy.c
> >
> > /* strcopy.c written by detour-at-metalshell.com
> > *
> > * example of a string copying function.
> > *
> > * http://www.metalshell.com/
> > *
> > */
> >
> > #include
> > #include
> >
> > void strcopy(const char *, char *);
> >
> > int main() {
> > char string1[] = "This is string1";
> > char string2[] = "This is string2";
> >
> > strcopy(string1, string2);
> > printf("String2: %s", string2);
> > }
> >
> > void strcopy(const char * str1, char * str2) {
> > int x = 0;
> >
> > /* change the size of string2 to the size of string1 */
> > realloc(str2, sizeof(str1));
> >
> > do {
> > str2[x] = str1[x];
> > } while (str1[x++] != '\0');
> >
> > }
>
>
> This program is incorrect.
> YOU CANNOT overwrite the contents of string2.
Why not? It is not a string literal.
> It is also illegal to
> realloc() a pointer which was not obtained by malloc().
> also, realloc is free to move the block. you have to use its return
> value to update the pointer. There's just so much wrong...
>
> I DON'T RECOMMEND learning from this example.
>
I agree. There is no reason to rewrite strncpy
Ruben
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