Re: strcpy versus strncpy

[cmason () WYREX COM (Chris L. Mason)]

> It is kalled SIGSEGV ...
> Because strlen is simply an
> size_t i; char *string;
> for(i=0;*(string+i)!='\0';i++);
> return i;
>
> And when (string+1) points outside the space allocated .. well .. possible
> it doesn't find a '\0' there .. possible it don't even can read it ..
>
> And thats why you can't do that.

Good point.  Here's a revised version (also incorporating other suggestions
made)

size_t sstrlen(const char *s, size_t n) {
    size_t  i;

    for(i = 0; (*(s+i) != '\0' && i < n); i++);

        return i;
}

char *sstrncpy(char *dst, size_t n1, const char *src, size_t n2) {
    if (sstrlen(src, n2) > (n1 - 1)) {
        errno = ENOSPC;
        dst[0] = NULL;
        return NULL;
    }

    strncpy(dst, src, n2);

    return dst;
}

Something similar could be done with strncat as well.  Note that I
don't return the number of bytes written because I wanted to remain
consistent with the existing strncpy.


Chris