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 an-
       gle) 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  at-
       tributes(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 5.05 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)