clog (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);

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.

SEE ALSO

cabs(3), cexp(3), clog10(3), clog2(3), complex(7)

COLOPHON

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