1SQRT(P)                    POSIX Programmer's Manual                   SQRT(P)
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NAME

6       sqrt, sqrtf, sqrtl - square root function
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SYNOPSIS

9       #include <math.h>
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11       double sqrt(double x);
12       float sqrtf(float x);
13       long double sqrtl(long double x);
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15

DESCRIPTION

17       These  functions  shall  compute  the  square root of their argument x,
18       sqrt(x).
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20       An application wishing to check for error situations should  set  errno
21       to  zero  and  call  feclearexcept(FE_ALL_EXCEPT)  before calling these
22       functions.  On return, if errno is non-zero or  fetestexcept(FE_INVALID
23       |  FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero, an error has
24       occurred.
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RETURN VALUE

27       Upon successful completion, these functions  shall  return  the  square
28       root of x.
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30       For  finite values of x < -0, a domain error shall occur, and  either a
31       NaN (if supported),  or    an  implementation-defined  value  shall  be
32       returned.
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34       If x is NaN, a NaN shall be returned.
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36       If x is ±0 or +Inf, x shall be returned.
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38       If  x  is  -Inf,  a domain error shall occur, and either a NaN (if sup‐
39       ported), or an implementation-defined value shall be returned.
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ERRORS

42       These functions shall fail if:
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44       Domain Error
45              The finite value of x is < -0,    or x is -Inf.
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47       If the integer expression (math_errhandling & MATH_ERRNO) is  non-zero,
48       then   errno  shall  be  set  to  [EDOM].  If  the  integer  expression
49       (math_errhandling &  MATH_ERREXCEPT)  is  non-zero,  then  the  invalid
50       floating-point exception shall be raised.
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53       The following sections are informative.
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EXAMPLES

56   Taking the Square Root of 9.0
57              #include <math.h>
58              ...
59              double x = 9.0;
60              double result;
61              ...
62              result = sqrt(x);
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APPLICATION USAGE

65       On   error,   the   expressions  (math_errhandling  &  MATH_ERRNO)  and
66       (math_errhandling & MATH_ERREXCEPT) are independent of each other,  but
67       at least one of them must be non-zero.
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RATIONALE

70       None.
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FUTURE DIRECTIONS

73       None.
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SEE ALSO

76       feclearexcept()  , fetestexcept() , isnan() , the Base Definitions vol‐
77       ume of IEEE Std 1003.1-2001, Section 4.18, Treatment  of  Error  Condi‐
78       tions for Mathematical Functions, <math.h>, <stdio.h>
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81       Portions  of  this text are reprinted and reproduced in electronic form
82       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
83       --  Portable  Operating  System  Interface (POSIX), The Open Group Base
84       Specifications Issue 6, Copyright (C) 2001-2003  by  the  Institute  of
85       Electrical  and  Electronics  Engineers, Inc and The Open Group. In the
86       event of any discrepancy between this version and the original IEEE and
87       The  Open Group Standard, the original IEEE and The Open Group Standard
88       is the referee document. The original Standard can be  obtained  online
89       at http://www.opengroup.org/unix/online.html .
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93IEEE/The Open Group                  2003                              SQRT(P)
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