**NAME**

carg, cargf, cargl - calculate the argument

**SYNOPSIS**

**#include** **<complex.h>**
**double** **carg(double** **complex** __z__**);**
**float** **cargf(float** **complex** __z__**);**
**long** **double** **cargl(long** **double** **complex** __z__**);**
Link with __-lm__.

**DESCRIPTION**

A complex number can be described by two real coordinates. One may use
rectangular coordinates and gets
z = x + I * y
where __x__ __=__ __creal(z)__ and __y__ __=__ __cimag(z)__.
Or one may use polar coordinates and gets
z = r * cexp(I * a)
where __r__ __=__ __cabs(z)__ is the "radius", the "modulus", the absolute value of
__z__, and __a__ __=__ __carg(z)__ is the "phase angle", the argument of __z__.
One has:
tan(carg(z)) = cimag(z) / creal(z)

**RETURN** **VALUE**

The return value is the range of [-pi,pi].

**VERSIONS**

These functions first appeared in glibc in version 2.1.

**CONFORMING** **TO**

C99.

**SEE ALSO**

**cabs**(3), **complex**(7)

**COLOPHON**

This page is part of release 3.24 of the Linux __man-pages__ project. A
description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.
2008-08-11