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

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                                                   2017-09-15                                            CARG(3)