| .\" Copyright 2002 Walter Harms (walter.harms@informatik.uni-oldenburg.de) |
| .\" |
| .\" %%%LICENSE_START(GPL_NOVERSION_ONELINE) |
| .\" Distributed under GPL |
| .\" %%%LICENSE_END |
| .\" |
| .TH CARG 3 2021-03-22 "" "Linux Programmer's Manual" |
| .SH NAME |
| carg, cargf, cargl \- calculate the complex argument |
| .SH SYNOPSIS |
| .nf |
| .B #include <complex.h> |
| .PP |
| .BI "double carg(double complex " z ");" |
| .BI "float cargf(float complex " z ");" |
| .BI "long double cargl(long double complex " z ");" |
| .PP |
| Link with \fI\-lm\fP. |
| .fi |
| .SH DESCRIPTION |
| These functions calculate the complex argument (also called phase angle) of |
| .IR z , |
| with a branch cut along the negative real axis. |
| .PP |
| A complex number can be described by two real coordinates. |
| One may use rectangular coordinates and gets |
| .PP |
| .nf |
| z = x + I * y |
| .fi |
| .PP |
| where |
| .IR "x\ =\ creal(z)" |
| and |
| .IR "y\ =\ cimag(z)" . |
| .PP |
| Or one may use polar coordinates and gets |
| .PP |
| .nf |
| z = r * cexp(I * a) |
| .fi |
| .PP |
| where |
| .IR "r\ =\ cabs(z)" |
| is the "radius", the "modulus", the absolute value of |
| .IR z , |
| and |
| .IR "a\ =\ carg(z)" |
| is the "phase angle", the argument of |
| .IR z . |
| .PP |
| One has: |
| .PP |
| .nf |
| tan(carg(z)) = cimag(z) / creal(z) |
| .fi |
| .SH RETURN VALUE |
| The return value is in the range of [\-pi,pi]. |
| .SH VERSIONS |
| These functions first appeared in glibc in version 2.1. |
| .SH ATTRIBUTES |
| For an explanation of the terms used in this section, see |
| .BR attributes (7). |
| .ad l |
| .nh |
| .TS |
| allbox; |
| lbx lb lb |
| l l l. |
| Interface Attribute Value |
| T{ |
| .BR carg (), |
| .BR cargf (), |
| .BR cargl () |
| T} Thread safety MT-Safe |
| .TE |
| .hy |
| .ad |
| .sp 1 |
| .SH CONFORMING TO |
| C99, POSIX.1-2001, POSIX.1-2008. |
| .SH SEE ALSO |
| .BR cabs (3), |
| .BR complex (7) |
