In this case, you don't have to look far to see that you can't use the
return value of printf.
According to my manpage, printf returns 0 on success, 1 on failure. No
mention of the number of characters written. This is different with
sprintf/snprintf (see e.g
http://www.opengroup.org/onlinepubs/000095399/functions/snprintf.html),
but IIRC a number of platforms don't implement those according to the
standard anyway.
I suppose that the most portable way to achieve what you want here is
to write to a temporary string, then compare the lengths of the
temporary strings... Or just add a call to _set_printf_count_output in
the relevant place, since AFAIK %n is still a standard-mandated printf
format flag.
[Shameless *nix zealot plug] Or use a Real Operating System ;-)
// Simon
On 6/6/07, Olivier Hainque <[EMAIL PROTECTED]> wrote:
Hello,
genmodes.c uses the %n capabilities of printf to compute the width of
pieces it outputs. This causes troubles on Windows Vista, because ...
<< Because of security reasons, support for the %n format specifier is
disabled by default in printf and all its variants. ... the default
behavior is to invoke the invalid parameter handler ...
>>
[http://msdn2.microsoft.com/en-us/library/ms175782%28VS.80%29.aspx]
It seems to me that we could replace the uses of %n by uses of printf
return values. I'm not clear whether this would be considered portable
enough, however.
Opinions ?
Thanks in advance,
Olivier
