carg (3)
Leading comments
Copyright 2002 Walter Harms (walter.harms@informatik.uni-oldenburg.de) %%%LICENSE_START(GPL_NOVERSION_ONELINE) Distributed under GPL %%%LICENSE_END
NAME
carg, cargf, cargl - calculate the complex argumentSYNOPSIS
#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 |