CARG(3) Linux Programmer s Manual CARG(3)

NAME carg, cargf, cargl - calculate the 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 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.


SEE ALSO cabs(3), complex(7)

COLOPHON This page is part of release 3.22 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at

2008-08-11 CARG(3)