'\" te
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.TH sqrt 3M "12 Jul 2006" "SunOS 5.11" "Mathematical Library Functions"
.SH NAME
sqrt, sqrtf, sqrtl \- square root function
.SH SYNOPSIS
.LP
.nf
c99 [ \fIflag\fR... ] \fIfile\fR... \fB-lm\fR [ \fIlibrary\fR... ]
#include <math.h>

\fBdouble\fR \fBsqrt\fR(\fBdouble\fR \fIx\fR);
.fi

.LP
.nf
\fBfloat\fR \fBsqrtf\fR(\fBfloat\fR \fIx\fR);
.fi

.LP
.nf
\fBlong double\fR \fBsqrtl\fR(\fBlong double\fR \fIx\fR);
.fi

.SH DESCRIPTION
.sp
.LP
These functions compute the square root of their argument \fIx\fR.
.SH RETURN VALUES
.sp
.LP
Upon successful completion, these functions return the square root of \fIx\fR.
.sp
.LP
For finite values of \fIx\fR < \(mi0, a domain error occurs and either a NaN
(if supported) or an implementation-defined value is returned.
.sp
.LP
If \fIx\fR is NaN, a NaN is returned.
.sp
.LP
If \fIx\fR is \(+-0 or +Inf, \fIx\fR is returned.
.sp
.LP
If \fIx\fR is \(miInf, a domain error occurs and a NaN is returned.
.SH ERRORS
.sp
.LP
These functions will fail if:
.sp
.ne 2
.mk
.na
\fBDomain Error\fR
.ad
.RS 16n
.rt  
The finite value of \fIx\fR is < \(mi0 or \fIx\fR is \(miInf.
.sp
If the integer expression (\fBmath_errhandling\fR & \fBMATH_ERREXCEPT\fR) is
non-zero, the invalid floating-point exception is raised.
.sp
The \fBsqrt()\fR function sets \fBerrno\fR to \fBEDOM\fR if the value of
\fIx\fR is negative.
.RE

.SH USAGE
.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.
.sp
.LP
An application can also set \fBerrno\fR to 0 before calling \fBsqrt()\fR. On
return, if \fBerrno\fR is non-zero, an error has occurred. The \fBsqrtf()\fR
and \fBsqrtl()\fR functions do not set \fBerrno\fR.
.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
\fBfeclearexcept\fR(3M), \fBfetestexcept\fR(3M), \fBisnan\fR(3M),
\fBmath.h\fR(3HEAD), \fBattributes\fR(5), \fBstandards\fR(5)