newlib-cygwin/newlib/libm/complex/carg.c

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/* $NetBSD: carg.c,v 1.1 2007/08/20 16:01:31 drochner Exp $ */
/*
* Written by Matthias Drochner <drochner@NetBSD.org>.
* Public domain.
*
* imported and modified include for newlib 2010/10/03
* Marco Atzeri <marco_atzeri@yahoo.it>
*/
/*
FUNCTION
<<carg>>, <<cargf>>---argument (phase angle)
INDEX
carg
INDEX
cargf
ANSI_SYNOPSIS
#include <complex.h>
double carg(double complex <[z]>);
float cargf(float complex <[z]>);
DESCRIPTION
These functions compute the argument (also called phase angle)
of <[z]>, with a branch cut along the negative real axis.
<<cargf>> is identical to <<carg>>, except that it performs
its calculations on <<floats complex>>.
RETURNS
@ifnottex
The carg functions return the value of the argument in the
interval [-pi, +pi]
@end ifnottex
@tex
The carg functions return the value of the argument in the
interval [$-\pi$, $+\pi$]
@end tex
PORTABILITY
<<carg>> and <<cargf>> are ISO C99
QUICKREF
<<carg>> and <<cargf>> are ISO C99
*/
#include <complex.h>
#include <math.h>
double
carg(double complex z)
{
return atan2( cimag(z) , creal(z) );
}