Manual of CTAN(3) (v2.55)

Linux Programmer's Manual

NAME

ctan, ctanf, ctanl - complex tangent function

#include <complex.h>

double complex ctan(double complex z);
float complex ctanf(float complex z);
long double complex ctanl(long double complex z);

Link with -lm.

The complex tangent function ctan(z) is defined mathematically as csin(z) / ccos(z).

C99