HP-UX Reference (11i v2 04/09) - 3 Library Functions A-M (vol 6)

ManualsBrandsHP ManualsSoftwareHP-UX Reference Manuals

100

asin(3M) asin(3M)

NAME

asin(), asinf(), asinl(), asinw(), asinq() - arcsine functions

SYNOPSIS

#include <math.h>

double asin(double x);

float asinf(float x);

Itanium-based Systems Only

long double asinl(long double x);

extended asinw(extended x);

quad asinq(quad x);

DESCRIPTION

asin() returns the arcsine of x, in the range −Pi/2 to Pi/2.

asinf() is a float version of asin()

; it takes a float argument and returns a float result.

Itanium-based Systems Only

asinl() is a long double version of asin(); it takes a long double argument and returns a

long double result.

asinw() is an extended version of asin(); it takes an extended argument and returns an

extended result.

asinq() is equivalent to asinl() on HP-UX systems.

USAGE

To use these functions compile either with the default

-Ae option or with the -Aa

and the

-D_HPUX_SOURCE options.

To use (for Itanium-based systems)

asinw() or asinq(), compile also with the -fpwidetypes

option.

To use any of these functions, make sure your program includes

<math.h>, and link in the math library

by specifying -lm on the compiler or linker command line.

For more information, see the HP-UX Floating-Point Guide.

PA-RISC Systems Only

Millicode versions of the asin() and asinf() functions are available. Millicode versions of math

library functions are usually faster than their counterparts in the standard library. To use these ver-

sions, compile your program with the +Olibcalls or the +Oaggressive optimization option.

For special cases, the millicode versions return the values described in the RETURN VALUE section, but

do not set

errno.

RETURN VALUE

asin(±0) returns ±0.

If the magnitude of x is greater than one,

asin() returns NaN and raises the invalid exception.

If x is NaN,

asin() returns NaN.

When it raises no other exception, whether

asin() raises the inexact exception is unspeciﬁed.

ERRORS

If the magnitude of x is greater than one,

asin() sets errno to [EDOM].

Itanium-based Systems Only

HP-UX

libm functions on Itanium-based system do not set errno by default. For errno setting, com-

pile with the +Olibmerrno option.