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<H2> powi </H2>
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<H3> Syntax                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       </H3>
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<P>

<TABLE><tr><td>&nbsp;</td><td class=example><pre>#include &#60;math.h&#62;

double powi(double x, int iy);
</pre></td></tr></table></P><P>

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<H3> Description                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    </H3>
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<P>

This function computes <EM>x^iy</EM>, where <VAR>iy</VAR> is an integer number.
It does so by an optimized sequence of squarings and multiplications.
For integer values of exponent, it is always faster to call <CODE>powi</CODE>
than to call <CODE>pow</CODE> with the same arguments, even if <VAR>iy</VAR> has a
very large value.  For small values of <VAR>iy</VAR>, <CODE>powi</CODE> is
<EM>much</EM> faster than <CODE>pow</CODE>.
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<H3> Return Value                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            </H3>
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<VAR>x</VAR> raised to the <VAR>iy</VAR> power.  If <VAR>x</VAR> and <VAR>iy</VAR> are both
zero, the return value is 1.  If <VAR>x</VAR> is equal to zero, and <VAR>iy</VAR>
is negative, the return value is <CODE>Inf</CODE>.  This function never sets
<CODE>errno</CODE>.
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<H3> Portability                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    </H3>
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<P>

<TABLE>
<TR><TD>ANSI/ISO C</TD>
</TD><TD> No
</TR>
<TR><TD>POSIX</TD>
</TD><TD> No
</TR></TABLE>
<P>

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