lvqcl wrote:
> Why? We can use vsnprintf_s for MSVS, and vsnprintf for MinGW.
>
> MSVS version of vsnprintf_s is located inside (statically linked) msvcp???.lib
> or (dynamically linked) msvcp???.dll. They are part of MSVS runtime, and
> compatible
> with WinXP. So it is safe to use it in FLAC.
Oh, ok. I missed this bit. I know so very little about Windows.
However, if you compile flac on say Win7 using vsnprintf_s and then take
the dynamically compiled binary to WinXP it will fail, right?
> As you see, MSVC version of vsnprintf can return positive value
> even when it didn't write '\0' at the end. So
> if (rc < 0) { ... str [...] = 0; }
> is not enough.
Like I said, untested. It was the first thing that came into my head version
of the code :-).
> What about this version --
>
> int flac_snprintf(char *str, size_t size, const char *fmt, ...)
> {
> va_list va;
> int rc;
>
> va_start (va, fmt);
>
> #if defined _MSC_VER
> rc = vsnprintf_s (str, size, _TRUNCATE, fmt, va);
> if (rc < 0)
> rc = size - 1;
> #elif defined __MINGW32__ && (!defined __USE_MINGW_ANSI_STDIO ||
> __USE_MINGW_ANSI_STDIO == 0)
> rc = vsnprintf (str, size, fmt, va);
> if (rc < 0 || rc == size) {
> rc = size - 1;
> str [rc] = '\0'; /* assert(size > 0) */
> }
> #else
> rc = vsnprintf (str, size, fmt, va);
> #endif
> va_end (va);
>
> return rc;
> }
I like that but ....
> Or forget about __USE_MINGW_ANSI_STDIO:
>
> int flac_snprintf(char *str, size_t size, const char *fmt, ...)
> {
> va_list va;
> int rc;
>
> va_start (va, fmt);
>
> #if defined _MSC_VER || defined __MINGW32__
> rc = vsnprintf (str, size, fmt, va);
> if (rc < 0 || rc == size) {
> rc = size - 1;
> str [rc] = '\0'; /* assert(size > 0) */
> }
> #else
> rc = vsnprintf (str, size, fmt, va);
> #endif
> va_end (va);
>
> return rc;
> }
This one has the advantage of simplicity, there are only two things
to test.
Either of those two are fine. You choose and send a patch. I'll write
a unit test for flac_snprintf to capture our assumptions.
Cheers,
Erik
--
----------------------------------------------------------------------
Erik de Castro Lopo
http://www.mega-nerd.com/
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