Re: [patch] Use inttypes macros for size_t format string

[Jakub Jelen <jjelen@xxxxxxxxxx>]

On Thu, 2020-01-16 at 11:54 +0100, Andreas Schneider wrote:
> On Thursday, 16 January 2020 11:51:48 CET Andreas Schneider wrote:
> > On Wednesday, 15 January 2020 17:46:30 CET g4-lisz@xxxxxxxxxxxx
> > wrote:
> > > On 15.01.20 17:32, Andreas Schneider wrote:
> > > > On Wednesday, 15 January 2020 14:35:39 CET Jakub Jelen wrote:
> > > > > On Wed, 2020-01-15 at 13:01 +0100, g4-lisz@xxxxxxxxxxxx
> > > > > wrote:
> > > > > > Hi there, here's a patch for fixing a printf format string
> > > > > > issue when
> > > > > > compiling with MinGW (and possibly other
> > > > > > "architectures"...).
> > > > > > 
> > > > > > A big thanks to Zdenek OGAR Skalak for the hint!
> > > > > 
> > > > > Looks good to me. Grepping through the rest of the code shows
> > > > > that
> > > > > there will most probably be more issues like this:
> > > > > 
> > > > > $ git grep "PRIdS" | wc -l
> > > > > 10
> > > > > $ git grep "%zu" | wc -l
> > > > > 27
> > > > > 
> > > > > Could you check also the other cases to make sure we can
> > > > > address it in
> > > > > the whole codebase?
> > > > > 
> > > > > Andreas, what do you suggest to make sure we do not introduce
> > > > > new
> > > > > issues like this?
> > > > 
> > > > %zu is ANSI C99
> > > > 
> > > > https://en.cppreference.com/w/c/io/fprintf
> > > > 
> > > > That's more than 20 years old now. We had PRIdS because Visual
> > > > Studio
> > > > didn't have %zu support for a long time. So we should replace
> > > > PRIdS with
> > > > %zu ;-)
> > > > 
> > > > 
> > > > Till, I'm sorry but you hit a compiler bug, open a bug against
> > > > MinGW.
> > > 
> > > It's not really a compiler bug. See here:
> > > https://stackoverflow.com/questions/44382862/how-to-printf-a-size-t-withou
> > > t-> warning-in-mingw-w64-gcc-7-1
> > According to that you need to compile with:
> > 
> > cmake -DCMAKE_C_FLAGS="-D__USE_MINGW_ANSI_STDIO=1" ..
> 
> Alternative seems to be:
> 
> -Dsnprintf=__mingw_snprintf -Dvsnprintf=__mingw_vsnprintf ...

Is this something that can be automatically done by some cmake check if
the mingw cross-compilation is detected?

Regards,
-- 
Jakub Jelen
Senior Software Engineer
Security Technologies
Red Hat, Inc.