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  10 .TH sqrt 3M "12 Jul 2006" "SunOS 5.11" "Mathematical Library Functions"
  11 .SH NAME
  12 sqrt, sqrtf, sqrtl \- square root function
  13 .SH SYNOPSIS
  14 .LP
  15 .nf
  16 c99 [ \fIflag\fR... ] \fIfile\fR... \fB-lm\fR [ \fIlibrary\fR... ]
  17 #include <math.h>
  18 
  19 \fBdouble\fR \fBsqrt\fR(\fBdouble\fR \fIx\fR);
  20 .fi
  21 
  22 .LP
  23 .nf
  24 \fBfloat\fR \fBsqrtf\fR(\fBfloat\fR \fIx\fR);
  25 .fi
  26 
  27 .LP
  28 .nf
  29 \fBlong double\fR \fBsqrtl\fR(\fBlong double\fR \fIx\fR);
  30 .fi
  31 
  32 .SH DESCRIPTION
  33 .sp
  34 .LP
  35 These functions compute the square root of their argument \fIx\fR.
  36 .SH RETURN VALUES
  37 .sp
  38 .LP
  39 Upon successful completion, these functions return the square root of \fIx\fR.
  40 .sp
  41 .LP
  42 For finite values of \fIx\fR < \(mi0, a domain error occurs and either a NaN
  43 (if supported) or an implementation-defined value is returned.
  44 .sp
  45 .LP
  46 If \fIx\fR is NaN, a NaN is returned.
  47 .sp
  48 .LP
  49 If \fIx\fR is \(+-0 or +Inf, \fIx\fR is returned.
  50 .sp
  51 .LP
  52 If \fIx\fR is \(miInf, a domain error occurs and a NaN is returned.
  53 .SH ERRORS
  54 .sp
  55 .LP
  56 These functions will fail if:
  57 .sp
  58 .ne 2
  59 .mk
  60 .na
  61 \fBDomain Error\fR
  62 .ad
  63 .RS 16n
  64 .rt  
  65 The finite value of \fIx\fR is < \(mi0 or \fIx\fR is \(miInf.
  66 .sp
  67 If the integer expression (\fBmath_errhandling\fR & \fBMATH_ERREXCEPT\fR) is
  68 non-zero, the invalid floating-point exception is raised.
  69 .sp
  70 The \fBsqrt()\fR function sets \fBerrno\fR to \fBEDOM\fR if the value of
  71 \fIx\fR is negative.
  72 .RE
  73 
  74 .SH USAGE
  75 .sp
  76 .LP
  77 An application wanting to check for exceptions should call
  78 \fBfeclearexcept\fR(\fBFE_ALL_EXCEPT\fR) before calling these functions. On
  79 return, if \fBfetestexcept\fR(\fBFE_INVALID\fR | \fBFE_DIVBYZERO\fR |
  80 \fBFE_OVERFLOW\fR | \fBFE_UNDERFLOW\fR) is non-zero, an exception has been
  81 raised. An application should either examine the return value or check the
  82 floating point exception flags to detect exceptions.
  83 .sp
  84 .LP
  85 An application can also set \fBerrno\fR to 0 before calling \fBsqrt()\fR. On
  86 return, if \fBerrno\fR is non-zero, an error has occurred. The \fBsqrtf()\fR
  87 and \fBsqrtl()\fR functions do not set \fBerrno\fR.
  88 .SH ATTRIBUTES
  89 .sp
  90 .LP
  91 See \fBattributes\fR(5) for descriptions of the following attributes:
  92 .sp
  93 
  94 .sp
  95 .TS
  96 tab() box;
  97 cw(2.75i) |cw(2.75i) 
  98 lw(2.75i) |lw(2.75i) 
  99 .
 100 ATTRIBUTE TYPEATTRIBUTE VALUE
 101 _
 102 Interface StabilityStandard
 103 _
 104 MT-LevelMT-Safe
 105 .TE
 106 
 107 .SH SEE ALSO
 108 .sp
 109 .LP
 110 \fBfeclearexcept\fR(3M), \fBfetestexcept\fR(3M), \fBisnan\fR(3M),
 111 \fBmath.h\fR(3HEAD), \fBattributes\fR(5), \fBstandards\fR(5)