carg(), cargf(), cargl()

Compute the argument of a complex number

Synopsis:

#include <complex.h>

double carg(double complex z);

float cargf(float complex z);

long double cargl(long double complex z);

libm

Use the -l m option to qcc to link against this library.

These functions compute the argument (or phase angle) of the complex number specified by z, with a branch cut along the negative real axis.

To check for error situations, use feclearexcept() and fetestexcept(). For example:

Call feclearexcept(FE_ALL_EXCEPT) before calling carg(), cargf(), or cargl().
On return, if fetestexcept(FE_ALL_EXCEPT) is nonzero, then an error has occurred.

If no errors occur, the argument of z, in the interval (-π; π).

Errors and special cases are handled as if the function were implemented as atan2 (cimag(z), creal(z)).

These functions raise FE_INEXACT if the FPU reports that the result can't be exactly represented as a floating-point number.