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Mathematical Library Functionspow(3M)


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:

ATTRIBUTE TYPEATTRIBUTE VALUE
MT-LevelMT-Safe

SEE ALSO

 

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


SunOS 5.9Go To TopLast Changed 29 Dec 1996

 
      
      
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