**carg**

**CARG(3)** Linux Programmer's Manual **CARG(3)**
NAME
carg, cargf, cargl - calculate the complex 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
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 the range of [-pi,pi].
VERSIONS
These functions first appeared in glibc in version 2.1.
ATTRIBUTES
For an explanation of the terms used in this section, see
**attributes(7)**.
+-------------------------+---------------+---------+
|Interface | Attribute | Value |
+-------------------------+---------------+---------+
|carg(), cargf(), cargl() | Thread safety | MT-Safe |
+-------------------------+---------------+---------+
CONFORMING TO
C99, POSIX.1-2001, POSIX.1-2008.
SEE ALSO
**cabs(3)**, **complex(7)**
COLOPHON
This page is part of release 4.15 of the Linux man-pages project. A
description of the project, information about reporting bugs, and the
latest version of this page, can be found at
https://www.kernel.org/doc/man-pages/.
2017-09-15 **CARG(3)**

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