carg(3)

NAME

carg, cargf, cargl - calculate the argument

#include <complex.h>
double carg(double complex z);
float cargf(float complex z);
long double cargl(long double complex z);
Link with -lm.

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.

C99.

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