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
Colophon
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Referenced By
atan(3), atan2(3), complex(7).
The man pages cargf(3) and cargl(3) are aliases of carg(3).