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.TH hypot 3M "1 Sep 2002" "SunOS 5.11" "Mathematical Library Functions"
.SH NAME
hypot, hypotf, hypotl \- Euclidean distance function
.SH SYNOPSIS
.LP
.nf
c99 [ \fIflag\fR... ] \fIfile\fR... \fB-lm\fR [ \fIlibrary\fR... ]
#include <math.h>

\fBdouble\fR \fBhypot\fR(\fBdouble\fR \fIx\fR, \fBdouble\fR \fIy\fR);
.fi

.LP
.nf
\fBfloat\fR \fBhypotf\fR(\fBfloat\fR \fIx\fR, \fBfloat\fR \fIy\fR);
.fi

.LP
.nf
\fBlong double\fR \fBhypotl\fR(\fBlong double\fR \fIx\fR, \fBlong double\fR \fIy\fR);
.fi

.SH DESCRIPTION
.sp
.LP
These functions compute the length of the square root of \fIx\fR^2 + \fIy\fR^2
without undue overflow or underflow.
.SH RETURN VALUES
.sp
.LP
Upon successful completion, these functions return the length of the hypotenuse
of a right angled triangle with sides of length \fIx\fR^2 and \fIy\fR^2.
.sp
.LP
If the correct value would cause overflow, a range error occurs and
\fBhypot()\fR, \fBhypotf()\fR, and \fBhypotl()\fR return the value of the macro
\fBHUGE_VAL\fR, \fBHUGE_VALF\fR, and \fBHUGE_VALL\fR, respectively.
.sp
.LP
If \fIx\fR or \fIy\fR is \(+-Inf, +Inf is returned even if one of \fIx\fR or
\fIy\fR is NaN.
.sp
.LP
If \fIx\fR or \fIy\fR is NaN and the other is not \(+-Inf, a NaN is returned.
.SH ERRORS
.sp
.LP
These functions will fail if:
.sp
.ne 2
.mk
.na
\fBRange Error\fR
.ad
.RS 15n
.rt  
The result overflows.
.sp
If the integer expression (\fBmath_errhandling\fR & \fBMATH_ERREXCEPT\fR) is
non-zero, the overflow floating-point exception is raised.
.RE

.SH USAGE
.sp
.LP
\fBhypot\fR(\fIx\fR,\fIy\fR), \fBhypot\fR(\fIy\fR,\fIx\fR), and
\fBhypot\fR(\fIx\fR, \(mi\fIy\fR) are equivalent.
.sp
.LP
\fBhypot\fR(\fIx\fR, \(+-0) is equivalent to \fBfabs\fR(\fIx\fR).
.sp
.LP
These functions takes precautions against underflow and overflow during
intermediate steps of the computation.
.sp
.LP
An application wanting to check for exceptions should call
\fBfeclearexcept\fR(\fBFE_ALL_EXCEPT\fR) before calling these functions. On
return, if \fBfetestexcept\fR(\fBFE_INVALID\fR | \fBFE_DIVBYZERO\fR |
\fBFE_OVERFLOW\fR | \fBFE_UNDERFLOW\fR) is non-zero, an exception has been
raised. An application should either examine the return value or check the
floating point exception flags to detect exceptions.
.SH ATTRIBUTES
.sp
.LP
See \fBattributes\fR(5) for descriptions of the following attributes:
.sp

.sp
.TS
tab() box;
cw(2.75i) |cw(2.75i) 
lw(2.75i) |lw(2.75i) 
.
ATTRIBUTE TYPEATTRIBUTE VALUE
_
Interface StabilityStandard
_
MT-LevelMT-Safe
.TE

.SH SEE ALSO
.sp
.LP
\fBfabs\fR(3M), \fBfeclearexcept\fR(3M), \fBfetestexcept\fR(3M),
\fBisnan\fR(3M), \fBmath.h\fR(3HEAD), \fBsqrt\fR(3M), \fBattributes\fR(5),
\fBstandards\fR(5)