cmath.h

• This is a Standard C++ Library file. You should @c #include this file
• in your programs, rather than any of the @a *.h implementation files.
• This is the C++ version of the Standard C Library header @c math.h,
• and its contents are (mostly) the same as that header, but are all
• contained in the namespace @c std (except for names which are defined
• as macros in C).