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CPROJ(3)                 BSD Library Functions Manual                 CPROJ(3)

NAME
     cproj -- projection onto the Riemann sphere

SYNOPSIS
     #include <complex.h>

     double complex
     cproj(double complex z);

     long double complex
     cprojl(long double complex z);

     float complex
     cprojf(float complex z);

DESCRIPTION
     cproj(z) computes the projection of a complex floating-point number z
     onto the Riemann sphere: for any finite z, cproj(z) = z, but all complex
     infinities (including infinities with one NaN part) project to positive
     infinity on the real axis.

     Specifically, if z = x + iy has an infinite part (one of x or y is infin-ity), infinity),
     ity), then cproj(z) is equivalent to INFINITY + I*copysign(0.0,cimag(z)).

NOTE
     cproj() projects onto the C99 "Riemann Sphere", which may not agree with
     the mathematical notion of the Riemann Sphere; in particular, it has two
     infinites (inf +- 0i) and four zeroes (+-0 +- 0i).

SEE ALSO
     complex(3)

STANDARDS
     The cproj() function conforms to ISO/IEC 9899:1999(E).

4th Berkeley Distribution      October 10, 2006      4th Berkeley Distribution