Computes inverse trigonometric functions.
IEEE Math Library (libm.a)
or System V Math Library (libmsaa.a)
double asin (x) double x;
long double asinl (x) long double x;
double acos (x) double x;
long double acosl (x) long double x;
double atan (x) double x;
long double atanl (x) long double x;
double atan2 (y, x) double y, x;
long double atan2l (x,y) long double y, x;
The asin and asinl subroutines return the principal value of the arc sine of x, in the range [-pi/2, pi/2].
The acos and acosl subroutines return the principal value of the arc cosine of x, in the range [0, pi].
The atan and atanl subroutines return the principal value of the arc tangent of x, in the range [-pi/2, pi/2].
The atan2 and atan2l subroutines return the principal value of the arc tangent of y/x, using the signs of both parameters to determine the quadrant of the return value. The return values are in the range [-pi, pi].
When using the libm.a (-lm) library:
asin, asinl, acos, acosl | Return a NaNQ and set the errno global variable to EDOM if the absolute value of the parameter is greater than 1. |
When using libmsaa.a (-lmsaa):
These error-handling procedures may be changed with the matherr subroutine when using the libmsaa.a (-lmsaa) library.
These subroutines are part of Base Operating System (BOS) Runtime.
The asinh, acosh, or atanh subroutine, matherr subroutine.
Subroutines Overview in AIX General Programming Concepts: Writing and Debugging Programs.
128-Bit long double Floating-Point Format in AIX Version 4.3 General Programming Concepts: Writing and Debugging Programs.