clog(3) — Linux manual pages

Linux manual pages	Section 3

Name

clog, clogf, clogl — natural logarithm of a complex number

Synopsis

#include <complex.h>

double complex clog( double complex z);

float complex clogf( float complex z);

long double complex clogl( long double complex z);

	Note
	Link with `−lm`.

DESCRIPTION

The logarithm clog() is the inverse function of the exponential cexp(3). Thus, if y = clog(z), then z = cexp(y). The imaginary part of y is chosen in the interval [−pi,pi].

One has:

    clog(z) = log(cabs(z)) + I * carg(z)

Note that z close to zero will cause an overflow.

VERSIONS

These functions first appeared in glibc in version 2.1.

CONFORMING TO

C99.

COLOPHON

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