Bug#244610: libc6-dev: No header file declares log2l().

[Daniel Jacobowitz <dan@debian.org>]

On Wed, Apr 21, 2004 at 02:17:01AM +0100, ryutaroh@it.ss.titech.ac.jp wrote:
> > Read /usr/include/bits/mathcalls.h.
> 
> Have you compiled a sample code with log2l() and <math.h>
> and checked whether a warning was displayed? I doubt it.
> 
> Could you compile the following code with "gcc -Wall"?
> 
> #include <math.h>
> 
> int main(void)
> {
>   long double a=0.1;
>   return (int) log2l(a);
> }
> 
> I got the following warning, which should not happen according
> to the manual page.
> 
> sh-2.05b$ gcc -Wall log2l.c -lm
> log2l.c: In function `main':
> log2l.c:6: warning: implicit declaration of function `log2l'

Have you read /usr/include/bits/mathcalls.h as GOTO-san suggested?  I
doubt it :)

#ifdef __USE_ISOC99
__BEGIN_NAMESPACE_C99
/* Compute base-2 exponential of X.  */
__MATHCALL (exp2,, (_Mdouble_ __x));

/* Compute base-2 logarithm of X.  */
__MATHCALL (log2,, (_Mdouble_ __x));
__END_NAMESPACE_C99
#endif

If you compile with -std=c99, the prototype will be visible.

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer