Where is C++'s math.h's double abs(double)?

[Steven King]

On Monday 02 April 2001  6:48, Benjamin Kosnik wrote:
> I don't know.
>
> How about that? It seems odd to me to have a math.h supplied with
> libstdc++-v3 that differs from /usr/include/math.h
>
> Can someoby check around and see what various other compiler/library
> vendors do?

According to their online docs, it looks like dinkumware's math.h declares 
double abs(double);

http://www.dinkumware.com/htm_cpl/math.html