# CPROJ

NAME

SYNOPSIS

DESCRIPTION

VERSIONS

ATTRIBUTES

CONFORMING TO

NOTES

SEE ALSO

COLOPHON

## NAME

cproj, cprojf,
cprojl − project into Riemann Sphere

## SYNOPSIS

**#include
<complex.h>**

**double
complex cproj(double complex** *z***); **

float complex cprojf(float complex *z***); **

long double complex cprojl(long double complex
*z***);**

Link with
*−lm*.

## DESCRIPTION

This function
projects a point in the plane onto the surface of a Riemann
Sphere, the one-point compactification of the complex plane.
Each finite point *z* projects to *z* itself.
Every complex infinite value is projected to a single
infinite value, namely to positive infinity on the real
axis.

## VERSIONS

These functions
first appeared in glibc in version 2.1.

## ATTRIBUTES

For an
explanation of the terms used in this section, see
**attributes**(7).

## CONFORMING TO

C99.

## NOTES

In glibc 2.11
and earlier, the implementation does something different (a
*stereographic* projection onto a Riemann Sphere).

## SEE ALSO

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

## COLOPHON

This page is
part of release 3.53 of the Linux *man-pages* project.
A description of the project, and information about
reporting bugs, can be found at
http://www.kernel.org/doc/man−pages/.