SIMPLE SOLUTIONS

# CARG, CARGF, CARGL - reference manual online

Calculate the complex argument.

Chapter
2015-04-19
```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);

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 coor‐
dinates 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.