Re: [PATCH 1/2] MSVC: vsnprintf in Visual Studio 2015 doesn't need SNPRINTF_SIZE_CORR any more

From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Mar 30, 2016, 07:49 UTC
Message-ID: <alpine.DEB.2.20.1603300946410.4690@virtualbox>
In-Reply-To: <CAHGBnuNkuiyk1uvJqT1_1UWOhpVTg+TxJ2QvepuMBpvOD8AyFw@mail.gmail.com>

Hi Sven & Sebastian,

On Tue, 29 Mar 2016, Sebastian Schuberth wrote:

> On Tue, Mar 29, 2016 at 9:13 PM, Sven Strickroth <sven@cs-ware.de> wrote:

ACK on the patch.

Show 25 quoted lines

> > diff --git a/compat/snprintf.c b/compat/snprintf.c
> > index 42ea1ac..0b11688 100644
> > --- a/compat/snprintf.c
> > +++ b/compat/snprintf.c
> > @@ -9,7 +9,7 @@
> >   * always have room for a trailing NUL byte.
> >   */
> >  #ifndef SNPRINTF_SIZE_CORR
> > -#if defined(WIN32) && (!defined(__GNUC__) || __GNUC__ < 4)
> > +#if defined(WIN32) && (!defined(__GNUC__) || __GNUC__ < 4) && (!defined(_MSC_VER) || _MSC_VER < 1900)
> >  #define SNPRINTF_SIZE_CORR 1
> >  #else
> >  #define SNPRINTF_SIZE_CORR 0
> 
> I wonder if the logic is (and was) sensible here. We assume that every
> non-__GNUC__ and non-_MSC_VER compiler on Windows requires the
> correction. Wouldn't it make sense to not assume requiring the
> correction unless we know the compiler has this bug? That is,
> shouldn't this better say
> 
> #if defined(WIN32) && (defined(__GNUC__) && __GNUC__ < 4) ||
> (defined(_MSC_VER) && _MSC_VER < 1900))
> #define SNPRINTF_SIZE_CORR 1
> #else
> #define SNPRINTF_SIZE_CORR 0

Since the standard on Windows always was MS Visual C, it should be assumed that compilers *other* than GCC followed Visual C's lead.

Of course, evidence speaks louder than assumptions.

Therefore I would prefer to keep the current version, at least until we encounter a case where it is incorrect.

Thanks, Johannes