carg, cargf, cargl - calculate the complex argument
#include <complex.h>
double carg(double complex z);
float cargf(float complex z);
long double cargl(long double complex z);
Link with
-lm.
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)
The return value is the range of [-pi,pi].
These functions first appeared in glibc in version 2.1.
For an explanation of the terms used in this section, see
attributes(7).
| Interface |
Attribute |
Value |
| carg (), cargf (), cargl () |
Thread safety |
MT-Safe |
C99, POSIX.1-2001, POSIX.1-2008.
cabs(3),
complex(7)