carg(3) Library Functions Manual carg(3)
NAME
carg, cargf, cargl - calculate the complex argument
LIBRARY
Math library (libm, -lm)
SYNOPSIS
#include <complex.h>
double carg(double complex z);
float cargf(float complex z);
long double cargl(long double complex z);
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 in the range of [-pi,pi].
ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7).
┌────────────────────────────────────────────┬───────────────┬─────────┐
│ Interface │ Attribute │ Value │
├────────────────────────────────────────────┼───────────────┼─────────┤
│ carg(), cargf(), cargl() │ Thread safety │ MT-Safe │
└────────────────────────────────────────────┴───────────────┴─────────┘
STANDARDS
C11, POSIX.1-2008.
HISTORY
glibc 2.1. C99, POSIX.1-2001.
SEE ALSO
cabs(3), complex(7)
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