cproj(3) Library Functions Manual cproj(3)

cproj, cprojf, cprojl - project into Riemann Sphere

Math library (libm, -lm)

#include <complex.h>
double complex cproj(double complex z);
float complex cprojf(float complex z);
long double complex cprojl(long double complex z);

These functions project 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.

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

Interface Attribute Value
cproj (), cprojf (), cprojl () Thread safety MT-Safe

C11, POSIX.1-2008.

glibc 2.1. C99, POSIX.1-2001.

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

cabs(3), complex(7)

2024-05-02 Linux man-pages 6.9