CARG

Section: Linux Programmer's Manual (3)
Updated: 2008-08-11
Index Return to Main Contents

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.

COLOPHON

This page is part of release 3.22 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/.