Zilog ZUSBOPTS - Manual (Page 426)

Standard Header Files UM017105-0511
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Zilog Developer Studio II – ZNEO™
User Manual
Mathematics
The < math.h > header declares several mathematical functions and defines one macro.
The functions take double-precision arguments and return double-precision values. Integer
arithmetic functions and conversion functions are discussed later.
The double data type is implemented as float in the ZNEO C-Compiler.
Macro
Treatment of Error Conditions
The behavior of each of these functions is defined for all values of its arguments. Each
function must return as if it were a single operation, without generating any externally vis-
ible exceptions.
For all functions, a domain error occurs if an input argument to the function is outside the
domain over which the function is defined. On a domain error, the function returns a spec-
ified value; the integer expression errno acquires the value of the EDOM macro.
Similarly, a range error occurs if the result of the function cannot be represented as a dou-
ble value. If the result overflows (the magnitude of the result is so large that it cannot be
represented in an object of the specified type), the function returns the value of the
HUGE_VAL macro, with the same sign as the correct value of the function; the integer
expression errno acquires the value of the ERANGE macro. If the result underflows (the
magnitude of the result is so small that it cannot be represented in an object of the speci-
fied type), the function returns zero.
Functions
Trigonometric
HUGE_VAL Expands to a positive double expression, not necessarily represented as
a float.
double acos(double x); Calculates arc cosine of x.
double asin(double x) Calculates arc sine of x.
double atan(double x); Calculates arc tangent of x.
double atan2(double y, double x); Calculates arc tangent of y/x.
double cos(double x); Calculates cosine of x.
Note: