1 | |
---|
2 | /* @(#)w_sqrt.c 5.1 93/09/24 */ |
---|
3 | /* |
---|
4 | * ==================================================== |
---|
5 | * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
---|
6 | * |
---|
7 | * Developed at SunPro, a Sun Microsystems, Inc. business. |
---|
8 | * Permission to use, copy, modify, and distribute this |
---|
9 | * software is freely granted, provided that this notice |
---|
10 | * is preserved. |
---|
11 | * ==================================================== |
---|
12 | */ |
---|
13 | |
---|
14 | /* |
---|
15 | FUNCTION |
---|
16 | <<sqrt>>, <<sqrtf>>---positive square root |
---|
17 | |
---|
18 | INDEX |
---|
19 | sqrt |
---|
20 | INDEX |
---|
21 | sqrtf |
---|
22 | |
---|
23 | SYNOPSIS |
---|
24 | #include <math.h> |
---|
25 | double sqrt(double <[x]>); |
---|
26 | float sqrtf(float <[x]>); |
---|
27 | |
---|
28 | DESCRIPTION |
---|
29 | <<sqrt>> computes the positive square root of the argument. |
---|
30 | You can modify error handling for this function with |
---|
31 | <<matherr>>. |
---|
32 | |
---|
33 | RETURNS |
---|
34 | On success, the square root is returned. If <[x]> is real and |
---|
35 | positive, then the result is positive. If <[x]> is real and |
---|
36 | negative, the global value <<errno>> is set to <<EDOM>> (domain error). |
---|
37 | |
---|
38 | |
---|
39 | PORTABILITY |
---|
40 | <<sqrt>> is ANSI C. <<sqrtf>> is an extension. |
---|
41 | */ |
---|
42 | |
---|
43 | /* |
---|
44 | * wrapper sqrt(x) |
---|
45 | */ |
---|
46 | |
---|
47 | #include "fdlibm.h" |
---|
48 | #include <errno.h> |
---|
49 | |
---|
50 | #ifndef _DOUBLE_IS_32BITS |
---|
51 | |
---|
52 | #ifdef __STDC__ |
---|
53 | double sqrt(double x) /* wrapper sqrt */ |
---|
54 | #else |
---|
55 | double sqrt(x) /* wrapper sqrt */ |
---|
56 | double x; |
---|
57 | #endif |
---|
58 | { |
---|
59 | #ifdef _IEEE_LIBM |
---|
60 | return __ieee754_sqrt(x); |
---|
61 | #else |
---|
62 | struct exception exc; |
---|
63 | double z; |
---|
64 | z = __ieee754_sqrt(x); |
---|
65 | if(_LIB_VERSION == _IEEE_ || isnan(x)) return z; |
---|
66 | if(x<0.0) { |
---|
67 | exc.type = DOMAIN; |
---|
68 | exc.name = "sqrt"; |
---|
69 | exc.err = 0; |
---|
70 | exc.arg1 = exc.arg2 = x; |
---|
71 | if (_LIB_VERSION == _SVID_) |
---|
72 | exc.retval = 0.0; |
---|
73 | else |
---|
74 | exc.retval = 0.0/0.0; |
---|
75 | if (_LIB_VERSION == _POSIX_) |
---|
76 | errno = EDOM; |
---|
77 | else if (!matherr(&exc)) { |
---|
78 | errno = EDOM; |
---|
79 | } |
---|
80 | if (exc.err != 0) |
---|
81 | errno = exc.err; |
---|
82 | return exc.retval; |
---|
83 | } else |
---|
84 | return z; |
---|
85 | #endif |
---|
86 | } |
---|
87 | |
---|
88 | #endif /* defined(_DOUBLE_IS_32BITS) */ |
---|