[Qt-interest] bug Qt 4.6-stable in qstrncpy

[Sylvain Pointeau]

Hi,
I think you are wrong.

extract from the qt documentation:

char * qstrncpy ( char * dst, const char * src, uint len )
A safe strncpy() function.
Copies at most len bytes from src (stopping at len or the terminating '\0'
whichever comes first) into dst and returns a pointer to dst. Guarantees
that dst is '\0'-terminated. If src or dst is 0, returns 0 immediately.
This function assumes that dst is at least len characters long.
beside :-) I use it for making a glue between C++ code and C code...

Cheers,
Sylvain


On Sun, Oct 11, 2009 at 3:34 PM, Thiago Macieira <thiago at kde.org> wrote:

> Em Domingo 11. Outubro 2009, às 15.04.10, Sylvain Pointeau escreveu:
> > I found a mistake in qstrncpy
> > it copies only the len-1 bytes
> > or more exactly it finishes by putting a 0 at len-1 which is obviously
> > wrong.
>
> That is intentional, so it's not a bug. The last parameter is not the
> length
> of the string you want to copy, but the size of the destination buffer.
>
> const char *original = "This is a very long string";
> char buf[5];
>
> qstrncpy(buf, original, sizeof buf);
>
> Result: buf contains "This";
>
> Besides, why are you using this function?
> --
> Thiago Macieira - thiago (AT) macieira.info - thiago (AT) kde.org
>  Senior Product Manager - Nokia, Qt Development Frameworks
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