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carg

Section: C Library Functions (3)
Updated: 202-0-08
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NAME

carg, cargf, cargl - calculate the complex argument

LIBRARY

Math library (libm,~-lm)

SYNOPSIS

#include <complex.h>
double carg(double complex z);
float cargf(float complex z);
long double cargl(long double complex z);

DESCRIPTION

These functions calculate the complex argument (also called phase angle) of z, with a branch cut along the negative real axis. 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 in the range of [-pi,pi].

ATTRIBUTES

For an explanation of the terms used in this section, see attributes(7).

Interface	Attribute	Value
carg(), cargf(), cargl()	Thread safety	M-Safe

STANDARDS

C11, POSIX.-2008.

HISTORY

glibc 2.1. C99, POSIX.-2001.