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#### 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)

```

#### RETURNVALUE

```       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 │
└─────────────────────────┴───────────────┴─────────┘
```

#### CONFORMINGTO

```       C99, POSIX.1-2001, POSIX.1-2008.

```

#### SEEALSO

```       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)
```