[flac-dev] snprintf and MS Visual Studio

[Ben Allison]

Microsoft provides a surprisingly good (but proprietary) API inside strsafe.h.  StringCchPrintfA can be substituted for snprintf but the return value is different.   A small wrapper function around StringCchPrintfExA could get you enough information to emulate snprintf well.  But sprintf_s might be good enough for the limited uses inside flac, as you said.

Sent from my iPhone

On Mar 14, 2013, at 9:09 PM, Erik de Castro Lopo <mle+la at mega-nerd.com> wrote:

> Christoph Terasa wrote:
> 
>> Since MS refuses to support C99, the common practice is to use either
>> 
>>     sprintf_s: 
>> http://msdn.microsoft.com/en-us/library/ce3zzk1k(v=VS.80).aspx
>>    _snprintf_s: 
>> http://msdn.microsoft.com/de-de/library/f30dzcf6(v=VS.80).aspx
>> 
>> The former can be used as a drop-in replacement of snprintf via a 
>> define, the latter takes an additional argument count which can limit 
>> the bytes written to the buffer additionally.
> 
> Hmm, the first can be used as a drop-in replacement for many but
> not all uses of ISO C99 snprintf. For the uses in FLAC, it should
> be sufficient, we just have to be careful not to rely on the return
> value.
> 
>> DO NOT use
>>    _snprintf: 
>> http://msdn.microsoft.com/de-de/library/2ts7cx93(v=vs.80).aspx
>> 
>> since this does not NULL terminate if the length of the buffer is equal 
>> to the given buffer size (or larger than), and this differs from the std 
>> behaviour as stated at e.g. http://linux.die.net/man/3/snprintf
> 
> Yes, now I remember, that one is horribly broken.
> 
> Erik
> -- 
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> Erik de Castro Lopo
> http://www.mega-nerd.com/
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