Re: [XaraXtreme-dev] Doubles and Strings

[Alex Bligh <alex@xxxxxxxxxxx>]

Martin Wuerthner wrote:
> When using sprintf et al., "%f" means double and "%lf" is undefined. 
> The reason is some arcane bit of C semantics that causes the supplied 
> value argument to be promoted to double anyway, so it does not make 
> any difference whether you pass a float or a double. For obvious 
> reasons, argument promotion does not apply to pointers, so the scanf 
> family of routines has to distinguish between float and double. A good 
> compiler checks the format string and the supplied pointer types and 
> issues a warning if they do not match. I was under the impression that 
> GCC does that.

camScanf works through varags, it's actually vswscanf that gets called,
with an argptr, so no opportunity for compile-time checks. That's
because wxFormatConverter gets in the way to convert (say)
%s to %ls, so the format string is the same on Unicode and non-Unicode.

Are you *SURE* %lf is undefined for output versions? That's really
very annoying especially as I've just converted them all over. I
thought superfluous size qualifiers were meant to be discarded...

Alex