casinl(3) - BetterMan

casinl(3)

complex arc sine

distropkg manpages-dev@6.9.1-1dataset 2026-04-01T06:19:02Z+debian+ec4110e+mandoc:1.14.6-4

Synopsis

#include <complex.h>
double complex casin(double complex 
z
);
float complex casinf(float complex 
z
);
long double complex casinl(long double complex 
z
);

—

NAME

casin, casinf, casinl - complex arc sine

LIBRARY

Math library (libm, -lm)

SYNOPSIS

bash

#include <complex.h>

bash

double complex casin(double complex \nz\n);\n
\nfloat complex casinf(float complex \nz\n);\n
\nlong double complex casinl(long double complex \nz\n);

DESCRIPTION

These functions calculate the complex arc sine of z. If y = casin(z), then z = csin(y). The real part of y is chosen in the interval [-pi/2,pi/2].

One has:

bash


\n
    casin(z) = -i clog(iz + csqrt(1 - z * z))

ATTRIBUTES

For an explanation of the terms used in this section, see attributes(7).

Interface	Attribute	Value
casin (), casinf (), casinl ()	Thread safety	MT-Safe

STANDARDS

C11, POSIX.1-2008.

HISTORY

glibc 2.1. C99, POSIX.1-2001.