Hi Jason,
On Mon, Jan 20, 2025 at 10:54:38AM -0500, Jason Yundt wrote:
> On Mon, Jan 20, 2025 at 03:22:05PM +0100, Alejandro Colomar wrote:
> > > + char *locale_pathname = malloc(locale_pathname_size);
> > > + if (locale_pathname == NULL) {
> > > + err(EXIT_FAILURE, "malloc");
> > > + }
> > > +\&
> > > + iconv_t cd = iconv_open(nl_langinfo(CODESET), "UTF\-32");
> > > + if (cd == (iconv_t) \- 1) {
> > > + err(EXIT_FAILURE, "iconv_open");
> > > + }
> > > + char *inbuf = (char *) utf32_pathname;
> > > + size_t inbytesleft = sizeof utf32_pathname;
> > > + char *outbuf = locale_pathname;
> > > + size_t outbytesleft = locale_pathname_size;
> > > + size_t iconv_result =
> > > + iconv(cd, &inbuf, &inbytesleft, &outbuf, &outbytesleft);
> > > + if (iconv_result == \-1) {
> > > + err(EXIT_FAILURE, "iconv");
> > > + }
> > > + // This ensures that the conversion is 100% complete.
> > > + // See iconv(3) for details.
> > > + iconv_result =
> > > + iconv(cd, NULL, &inbytesleft, &outbuf, &outbytesleft);
> > > + if (iconv_result == \-1) {
> > > + err(EXIT_FAILURE, "iconv");
> > > + }
> >
> > Do we really need two calls? Why?
>
> iconv(3) says “In each series of calls to iconv(), the last should be
> one with inbuf or *inbuf equal to NULL, in order to flush out any
> partially converted input.” To me, that quote makes it sound like you
> should always call iconv() at least twice and that inbuf (or *inbuf)
> should be NULL the last time that you call iconv(). I don’t know why
> the man page says that you should always call iconv() at least twice.
I suspect that we can call it just once since we provided enough space.
The conversion can stop for five reasons:
• An invalid multibyte sequence ...
• A multibyte sequence is encountered that is valid but that cannot be
translated to the character encoding of the output. ...
• The input byte sequence has been entirely converted, that is, *in‐
bytesleft has gone down to 0. In this case, iconv() returns the number
of nonreversible conversions performed during this call.
• An incomplete multibyte sequence is encountered in the input, ...
• The output buffer has no more room ...
I don't see anything listed that would make reasonable a second call.
Maybe we should improve the wording in iconv(3), but we should be
careful. For now I'll leave it untouched. But please call it only
once.
Cheers,
Alex
--
<https://www.alejandro-colomar.es/>
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