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

[g4-lisz@xxxxxxxxxxxx]

On 22.01.20 12:25, Tilo Eckert wrote:

> Am 22.01.2020 um 08:49 schrieb Andreas Schneider:
>> On Thursday, 16 January 2020 12:55:07 CET g4-lisz@xxxxxxxxxxxx wrote:
>>>>> 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 ...
>>> Yes i was a bit overhasty with this patch...
>>>
>>> I also found that _POSIX_SOURCE does the trick. This would be a bit more
>>> generic.
>>>
>>> But I realized that the binaries get bigger like that, probably because
>>> they link in more of their own implementations. Not sure, if this is a
>>> good thing...
>>>
>>> -Dsnprintf=__mingw_snprintf -Dvsnprintf=__mingw_vsnprintf looks like a
>>> good compromise to me. I will also test this.
>> Which route should we go? Just set _POSIX_SOURCE?
>>  
> None of them. If you want libssh to work on Windows when built without
> MinGW, %z must not be used at all. The Windows implementation of printf
> does not support it. You have to use typecasts to print size_t in a
> portable way.
>
> Defining __USE_MINGW_ANSI_STDIO directly has been deprecated and emits a
> warning in newer MinGW versions:
> https://osdn.net/projects/mingw/scm/git/mingw-org-wsl/commits/36fae3c324a1997356db40caa83d0fac512b9407
>
> Defining one of _XOPEN_SOURCE, _POSIX_C_SOURCE or _POSIX_SOURCE
> (deprecated) implicitly enables __USE_MINGW_ANSI_STDIO. MinGW replaces
> the printf and scanf function families with C99 compliant versions if
> any of the defines is set, leading to slightly larger binaries. However,
> that would only fix it if MinGW is used...
I was initially talking about compiling with MinGW...

For Windows I can find documentation of "z" as supported spezifier:
https://docs.microsoft.com/en-us/cpp/c-runtime-library/format-specification-syntax-printf-and-wprintf-functions?view=vs-2019#size-prefixes-for-printf-and-wprintf-format-type-specifiers

But not sure since when this is supported.

But anway: What is the advantage of using typecasts instead of a format
spezifier macro (see my patch)? You still have to use OS specific type
casts. Or I'm understanding this wrong?

I really had difficulties to find out which are the official sources of
MinGW. So it's not here any longer?
https://sourceforge.net/p/mingw/mingw-org-wsl/ci/6.0-exp/tree/mingwrt/include/_mingw.h.in

Regards,
Till