Le 2012-08-12 17:41, songbird a écrit :
> Francis Giraldeau wrote:
> ...
>> Hi,
>>
>> Valgrind reports an invalid read, while I think the program is valid.
>> The program uses stpncpy() instead of strcpy():
>>
>> #include <string.h>
>> #include <stdlib.h>
>> #include <stdio.h>
>>
>> int main(int argc, char **argv) {
>> char *dst =3D (char *) calloc(4, 1);
>> char *src =3D (char *) calloc(4, 1);
>> src[0] =3D 'a';
>> src[1] =3D 'b';
>> src[2] =3D 'c';
>> src[3] =3D '\0';
>> dst =3D stpncpy(dst, src, 3);
>> printf("%s %s\n", src, dst);
>> }
>>
>> The error is the following:
> ....
>
> from the manpage:
>
> "RETURN VALUE
> stpncpy() returns a pointer to the terminating null byte in dest, or,
> if dest is not null-terminated, dest + n."
>
Of course you are right! Thought, I just tested without updating dst and
the problem is raised anyway. The error is not caused in the printf(),
but in the stpncpy().
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
int main(int argc, char **argv) {
char *dst = (char *) calloc(4, 1);
char *src = (char *) calloc(4, 1);
src[0] = 'a';
src[1] = 'b';
src[2] = 'c';
src[3] = '\0';
stpncpy(dst, src, 3);
//printf("%s %s\n", src, dst);
free(dst);
free(src);
}
Cheers,
Francis
smime.p7s
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