atand(3M)

NAME

atand(), atandf() − degree-valued arctangent functions

SYNOPSIS

#include <math.h>

double atand(double x);

float atandf(float x);

DESCRIPTION

atand() is a degree-valued version of the atan() function. It returns the arctangent of x in the range −90 to 90.

atandf() is a float version of atand(); it takes a float argument and returns a float result. To use this function, compile either with the −Ae option or with the −Aa and −D_HPUX_SOURCE options. Otherwise, the compiler promotes the float argument to double, and the function returns incorrect results.

atand() and atandf() are not specified by any standard, but atandf() is named in accordance with the conventions specified in the "Future Library Directions" section of the ANSI C standard.

To use these functions, link in the math library by specifying −lm on the compiler or linker command line.

RETURN VALUE

If x is ±INFINITY, atand() returns ±90 respectively.

If x is NaN, atand() returns NaN.

If the correct value after rounding would be smaller in magnitude than MINDOUBLE, atand() returns zero.

ERRORS

No errors are defined.

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