CATAN(3) Linux Programmer s Manual CATAN(3)

NAME catan, catanf, catanl - complex arc tangents

SYNOPSIS #include <complex.h>

double complex catan(double complex z); float complex catanf(float complex z); long double complex catanl(long double complex z);

Link with -lm.

DESCRIPTION The catan() function calculates the complex arc tangent of z. If y = catan(z), then z = ctan(y). The real part of y is chosen in the interval [-pi/2,pi/2].

One has:

catan(z) = 1 / 2i clog((1 + iz) / (1 - iz))

VERSIONS These functions first appeared in glibc in version 2.1.


SEE ALSO ccos(3), clog(3), complex(7)

COLOPHON This page is part of release 3.22 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at

2008-08-11 CATAN(3)