On 4/6/23 23:21, Alejandro Colomar wrote:
> strlcat(3) is a slow call that shouldn't be emitted by an optimizing
> compiler (similar to how GCC optimizes strcat(3) to stpcpy(3)).
> 
> With that in mind, do we really want all this code?  Or maybe we just
> want to implement it in the simplest possible way?
> 
> I suggest the following alternative:
> 
> 
> size_t
> strlcat(char *restrict dst, const char *restrict src, size_t dsize)
> {
>     size_t  dlen = strlen(dst);

This needs to be strnlen(dst, dsize), to avoid passing a huge size to
strlcpy(3).  This seems a good reason for having defined behavior for
strlcpy(x, y, 0).

> 
>     return strlcpy(dst + dlen, src, dsize - dlen) + dlen;
> }
> 
> 
> In fact, that's the code I would expect that GCC should emit instead
> of calls to the actual strlcat(3).
> 
> (Disclaimer: I didn't test the code; it may likely have bugs)
> 
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