Manpages - carg.3

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 in 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).

C99, POSIX.1-2001, POSIX.1-2008.

*cabs*(3), *complex*(7)

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