bin/53870: C++ undeclares standard math functions like isinf()

[Michael van Elst]

>Number:         53870
>Category:       bin
>Synopsis:       C++ undeclares standard math functions like isinf()
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sat Jun 28 03:40:11 PDT 2003
>Closed-Date:
>Last-Modified:
>Originator:     Michael van Elst
>Release:        FreeBSD 5.1-CURRENT i386
>Organization:
dis-
>Environment:
System: FreeBSD dv2.dev.de.cw.net 5.1-CURRENT FreeBSD 5.1-CURRENT #0: Tue Jun 10 14:12:43 CEST 2003 root at dv2.dev.de.cw.net:/usr/src/sys/i386/compile/DV2 i386


	
>Description:
The following C++ program does not compile on FreeBSD5.*

#include <cmath>
void foo()
{
    double d;
    isinf(d);
}

The error message is:

c.cc: In function `void foo()':
c.cc:5: error: `isinf' undeclared (first use this function)
c.cc:5: error: (Each undeclared identifier is reported only once for each 
   function it appears in.)

This is caused by isinf() being a macro defined in math.h which is
then undef'd in the cmath header. The compiler _should_ then see the
underlying function implementation instead of the macro.

The same is true for some other functions declared in the near vicinity:

isinf()
isnan()
signbit()

and some others like fpclassify() and isfinite(). The latter however
do not exists as functions in libc.

The error appeared with the introduction of GCC3.3.

>How-To-Repeat:
See above
>Fix:

Add prototypes for isinf(), isnan(), signbit() functions to math.h.
Add function implementations for the other functions that are only
macros.

>Release-Note:
>Audit-Trail:
>Unformatted: