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**NAME**

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

**SYNOPSIS**

#include<complex.h>doublecomplexclog(doublecomplexz);floatcomplexclogf(floatcomplexz);longdoublecomplexclogl(longdoublecomplexz);Link with-lm.

**DESCRIPTION**

The logarithmclog() is the inverse function of the exponentialcexp(3). Thus, ify=clog(z), thenz=cexp(y). The imaginary part ofyis chosen in the interval [-pi,pi]. One has: clog(z) = log(cabs(z)) + I * carg(z) Note thatzclose 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**

This page is part of release 3.35 of the Linuxman-pagesproject. A description of the project, and information about reporting bugs, can be found at http://man7.org/linux/man- pages/. 2008-08-11 CLOG(3)