NAME

pow − power function

SYNOPSIS

cc [ flag ... ] file ... −lm [ library ... ]

#include <math.h>

double pow(double x, double y);

DESCRIPTION

The pow() function computes the value of x raised to the power y, xy. If x is negative, y must be an integer value. 

RETURN VALUES

Upon successful completion, pow() returns the value of x raised to the power y. 

If x is 0 and y is 0, 1.0 is returned. 

If y is NaN, or y is non-zero and x is NaN, NaN is returned.  If y is 0.0 and x is NaN, NaN is returned. 

If x is 0.0 and y is negative, −HUGE_VAL is returned and errno may be set to EDOM  or ERANGE. 

If the correct value would cause overflow, ±HUGE_VAL is returned, and errno is set to ERANGE. 

If the correct value would cause underflow to 0, 0 is returned and errno may be set to ERANGE. 

For exceptional cases, matherr(3M) tabulates the values to be returned as dictated by Standards other than XPG4. 

ERRORS

The pow() function will fail if:

EDOM The value of x is negative and y is non-integral. 

ERANGE The value to be returned would have caused overflow. 

The pow() function may fail if:

EDOM The value of x is 0.0 and y is negative. 

ERANGE The correct value would cause underflow. 

USAGE

An application wishing to check for error situations should set errno to 0 before calling pow().  If errno is non-zero on return, or the return value is NaN, an error has occurred. 

ATTRIBUTES

See attributes(5) for descriptions of the following attributes:

SEE ALSO

exp(3M), isnan(3M), matherr(3M), attributes(5), standards(5)

SunOS 5.6  —  Last change: 29 Dec 1996