clog, clogf, clogl - natural logarithm of a complex number
#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
.
These functions calculate the complex natural logarithm of z
, with a branch cut along the negative real axis.
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.
These functions first appeared in glibc in version 2.1.
For an explanation of the terms used in this section, see attributes(7).
Interface | Attribute | Value |
clog(), clogf(), clogl() | Thread safety | MT-Safe |
C99, POSIX.1-2001, POSIX.1-2008.
This page is part of release 5.10 of the Linux man-pages
project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.