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

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                              2015-04-19                           CARG(3)

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