Missing documentation: archive_entry_update_pathname_utf8() returns 1 on success

[haferburg]

As of 3.7.2, archive_entry_update_pathname_utf8() is undocumented. Please add documentation.

I'm not actually sure how it's supposed to work.

Here's the code

int
archive_entry_update_pathname_utf8(struct archive_entry *entry, const char *name)
{
	if (archive_mstring_update_utf8(entry->archive,
	    &entry->ae_pathname, name) == 0)
		return (1);
	if (errno == ENOMEM)
		__archive_errx(1, "No memory");
	return (0);
}

and

int
archive_mstring_update_utf8(struct archive *a, struct archive_mstring *aes,
    const char *utf8)
{
	struct archive_string_conv *sc;
	int r;

	if (utf8 == NULL) {
		aes->aes_set = 0;
		return (0); /* Succeeded in clearing everything. */
	}
//  ------8<-*snip*------8<-*snip*------8<-*snip*------8<-*snip*------8<-*snip*-----
	/* All conversions succeeded. */
	return (0);
}

So if archive_mstring_update_utf8() is successful, it returns 0, and this makes archive_entry_update_pathname_utf8() return 1. Which is quite unexpected. I thought 1 means EOF and 0 means OK. The intention would be clearer if the code would use a define like ARCHIVE_OK instead of a literal int.

And then there's this code in the tests:

	/* Skip test if archive_entry_update_pathname_utf8() is broken. */
	/* In particular, this is currently broken on Win32 because
	 * setlocale() does not set the default encoding for CP_ACP. */
	entry = archive_entry_new();
	if (archive_entry_update_pathname_utf8(entry, badname_utf8)) {
		archive_entry_free(entry);
		skipping("Cannot test conversion failures.");
		return;
	}
	archive_entry_free(entry);

Here a non-zero return value is apparently interpreted as a conversion failure. This seems wrong.

Also, the comment in that latter snippet indicates a limitation that should be mentioned in the documentation as well, right? Is this what causes #1264 or #358?