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.
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, compile either with the default
-Ae
option or with the
-Aa
and
-D_HPUX_SOURCE
options. Make sure your program includes
<math.h>.
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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