Bug#171851: More missing math.h prototypes

[Daniel Jacobowitz <dan@debian.org>]

On Mon, Dec 30, 2002 at 10:23:16AM -0500, H. S. Teoh wrote:
> Hi, I just confirmed that trunc() is missing from /usr/include/math.h.
> Furthermore, the following are also missing (referenced from the manpage
> of trunc()):
> - lrint
> - nearbyint
> - round
> 
> Oddly, these functions do *not* appear in the libc info pages. 
> Nevertheless, they are definitely in libm: 

How did you confirm that they were not in <math.h>?  Judging from your
previous messages, by using cpp or building a test program.  I always
recommend actually grepping around in /usr/include for them; it can be
enlightening.

Consider this case:
#ifdef __USE_ISOC99
/* Return X times (2 to the Nth power).  */
__MATHCALL (scalbln,, (_Mdouble_ __x, long int __n));

/* Round X to integral value in floating-point format using current
   rounding direction, but do not raise inexact exception.  */
__MATHCALL (nearbyint,, (_Mdouble_ __x));

/* Round X to nearest integral value, rounding halfway cases away from
   zero.  */
__MATHCALL (round,, (_Mdouble_ __x));

/* Round X to the integral value in floating-point format nearest but
   not larger in magnitude.  */
__MATHCALLX (trunc,, (_Mdouble_ __x), (__const__));


They are only declared in C99 mode.  I believe that is correct.

> This is on libc6 2.3.1-8. I'm not sure I understand why they are in the
> .so but not in any header files nor in the info docs. Are there some
> standard compliance issues here that I'm not aware of?

They're in my copy of the info docs.  Try:
  "info libc Arithmetic Arithmetic\ Functions Rounding\ Functions"

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer