clog(3) — Linux manual page

NAME | LIBRARY | SYNOPSIS | DESCRIPTION | ATTRIBUTES | STANDARDS | HISTORY | SEE ALSO

clog(3)                 Library Functions Manual                 clog(3)

NAME         top

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

LIBRARY         top

       Math library (libm, -lm)

SYNOPSIS         top

       #include <complex.h>

       double complex clog(double complex z);
       float complex clogf(float complex z);
       long double complex clogl(long double complex z);

DESCRIPTION         top

       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.

ATTRIBUTES         top

       For an explanation of the terms used in this section, see
       attributes(7).
       ┌─────────────────────────────────────┬───────────────┬─────────┐
       │ Interface                           Attribute     Value   │
       ├─────────────────────────────────────┼───────────────┼─────────┤
       │ clog(), clogf(), clogl()            │ Thread safety │ MT-Safe │
       └─────────────────────────────────────┴───────────────┴─────────┘

STANDARDS         top

       C11, POSIX.1-2008.

HISTORY         top

       glibc 2.1.  C99, POSIX.1-2001.

SEE ALSO         top

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

Linux man-pages (unreleased)     (date)                          clog(3)

Pages that refer to this page: cacos(3)casin(3)catan(3)cexp(3)clog10(3)clog2(3)log(3)complex(7)