"Dimitrie O. Paun" dpaun@rogers.com writes:
On October 30, 2003 07:28 pm, Ferenc Wagner wrote:
if (n > -1 && n < size) return p;size = min( size*2, n+1 );
if (n > -1 && (size_t)n < size) return p;size = min( size*2, (size_t)n+1 );Once at it, could you please explain to me what the hell is going on here (min)?
Well, the way I see it, it's just trying to minimize memory usage in a portable manner. Normally, vsnprintf() should return the necessary size of the buffer (in n), if the current size is too small.
In libc-2.1 and later, yes it should. According to MSDN (and pre-2.1 libc docs), it should not.
Now, the way the code it's written right now will not work if vsnprintf() returns -1 for failure.
It does on XP. The new conformance tests tells it all... If written correctly. See below.
Question is, do we really need to worry about vsnprintf() not returning the correct size of the required buffer?
Seems like this is the case under Windows. Not under any reasonable modern GNU/Linuxes. However, writing portable code is easy: if the returned value exceeds the buffer length, allocate that much memory and repeat once. No need to loop in this case.
By the way, I really managed to screw myself (and my gcc) up by mixing libc calls into winetests. After yesterday's cvs update, it started to behave really strange. It was sort of working before (creating temporary files under /tmp), but after the update it is creating a directory called "C:\TEMP\wctX" under programs/winetests... It took me some good time to realise this, and I could not stop laughing when I finally did. It is obviously some funny mixture of libc and msvcrt functions, probably due to ./configure recreating the Makefile... So I could use some clarification on this issue. What I think is:
Normally I use the Unix libc functions. If I #include "config.h" #include "wine/port.h" and -lwine_port, I use the Windows runtime (msvcrt). By prepending and underscore, I always get the msvcrt functions.
But what is the truth? The scanf.c test clearly contradicts the above theory. I may be better off using the _names to avoid this confusion...
Feri.