On Mon, Oct 12, 2020 at 05:19:46PM +0100, Andre Przywara wrote:
> With -Wsign-compare, compilers warn about a mismatching signedness
> in comparisons in the function get_node_by_path().
>
> Taking the difference between two pointers results in a signed ptrdiff_t
> type, which mismatches the unsigned type returned by strlen().
> Since "p" has been returned by a call to strchr() with "path" as its
> argument, we know for sure that it's bigger than "path", so the
> difference must be positive. So a cast to an unsigned type is valid.
>
> Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
Again, (size_t) would be more strictly correct, I think.
> ---
> livetree.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/livetree.c b/livetree.c
> index 8393637..b8d0745 100644
> --- a/livetree.c
> +++ b/livetree.c
> @@ -526,7 +526,7 @@ struct node *get_node_by_path(struct node *tree, const char *path)
> p = strchr(path, '/');
>
> for_each_child(tree, child) {
> - if (p && strprefixeq(path, p - path, child->name))
> + if (p && strprefixeq(path, (unsigned)(p - path), child->name))
> return get_node_by_path(child, p+1);
> else if (!p && streq(path, child->name))
> return child;
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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