7.3.9.4 The cproj functions

Synopsis

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

Description

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The cproj functions compute a projection of z onto the Riemann sphere: z projects to z except that all complex infinities (even those with one infinite part and one NaN part) project to positive infinity on the real axis. If z has an infinite part, then cproj(z) is equivalent to

INFINITY + I * copysign(0.0, cimag(z))

Returns

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The cproj functions return the value of the projection onto the Riemann sphere.