Hi Jim,
> I tried enabling -Wvla for coreutils and found that it provoked hundreds
> of warnings, all due to this:
>
> ../lib/gettext.h:262:3: error: variable length array 'msg_ctxt_id'\
> is used [-Werror=vla]
>
> That comes from this inline function from gettext.h:
>
> static const char *
> dcnpgettext_expr (const char *domain,
> const char *msgctxt, const char *msgid,
> const char *msgid_plural, unsigned long int n,
> int category)
> {
> size_t msgctxt_len = strlen (msgctxt) + 1;
> size_t msgid_len = strlen (msgid) + 1;
> const char *translation;
> #if _LIBGETTEXT_HAVE_VARIABLE_SIZE_ARRAYS
> char msg_ctxt_id[msgctxt_len + msgid_len];
> #else
> ...
Yes, as you can see this code uses variable-length arrays only
when the compiler supports it.
> Do we have a guarantee that that array dimension is reasonable?
Yes. While msgctxt and msgid normally rarely exceed 1 KB (because
of the principle to split at paragraph boundaries, so that translators
can compare an old and a new msgid, for msgids with plural, the
string is most often only a single sentence, that is, rarely larger
than 200 bytes.
> Have you compared the trade-offs of VLA-vs-malloc here?
Yes I did.
The problem is that the compiler does not know that I did.
You may want to propose a #pragma diagnostic ignore patch.
Bruno
--
In memoriam Rudolf Slánský <http://en.wikipedia.org/wiki/Rudolf_Slánský>
