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| 2 | /* @(#)w_hypot.c 5.1 93/09/24 */ |
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| 3 | /* |
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| 4 | * ==================================================== |
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| 5 | * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
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| 6 | * |
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| 7 | * Developed at SunPro, a Sun Microsystems, Inc. business. |
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| 8 | * Permission to use, copy, modify, and distribute this |
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| 9 | * software is freely granted, provided that this notice |
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| 10 | * is preserved. |
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| 11 | * ==================================================== |
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| 12 | */ |
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| 13 | |
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| 14 | /* |
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| 15 | FUNCTION |
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| 16 | <<hypot>>, <<hypotf>>---distance from origin |
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| 17 | INDEX |
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| 18 | hypot |
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| 19 | INDEX |
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| 20 | hypotf |
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| 21 | |
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| 22 | SYNOPSIS |
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| 23 | #include <math.h> |
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| 24 | double hypot(double <[x]>, double <[y]>); |
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| 25 | float hypotf(float <[x]>, float <[y]>); |
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| 26 | |
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| 27 | DESCRIPTION |
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| 28 | <<hypot>> calculates the Euclidean distance |
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| 29 | @tex |
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| 30 | $\sqrt{x^2+y^2}$ |
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| 31 | @end tex |
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| 32 | @ifnottex |
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| 33 | <<sqrt(<[x]>*<[x]> + <[y]>*<[y]>)>> |
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| 34 | @end ifnottex |
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| 35 | between the origin (0,0) and a point represented by the |
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| 36 | Cartesian coordinates (<[x]>,<[y]>). <<hypotf>> differs only |
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| 37 | in the type of its arguments and result. |
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| 38 | |
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| 39 | RETURNS |
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| 40 | Normally, the distance value is returned. On overflow, |
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| 41 | <<hypot>> returns <<HUGE_VAL>> and sets <<errno>> to |
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| 42 | <<ERANGE>>. |
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| 43 | |
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| 44 | You can change the error treatment with <<matherr>>. |
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| 45 | |
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| 46 | PORTABILITY |
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| 47 | <<hypot>> and <<hypotf>> are not ANSI C. */ |
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| 48 | |
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| 49 | /* |
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| 50 | * wrapper hypot(x,y) |
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| 51 | */ |
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| 52 | |
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| 53 | #include "fdlibm.h" |
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| 54 | #include <errno.h> |
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| 55 | |
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| 56 | #ifndef _DOUBLE_IS_32BITS |
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| 57 | |
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| 58 | #ifdef __STDC__ |
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| 59 | double hypot(double x, double y)/* wrapper hypot */ |
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| 60 | #else |
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| 61 | double hypot(x,y) /* wrapper hypot */ |
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| 62 | double x,y; |
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| 63 | #endif |
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| 64 | { |
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| 65 | #ifdef _IEEE_LIBM |
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| 66 | return __ieee754_hypot(x,y); |
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| 67 | #else |
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| 68 | double z; |
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| 69 | struct exception exc; |
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| 70 | z = __ieee754_hypot(x,y); |
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| 71 | if(_LIB_VERSION == _IEEE_) return z; |
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| 72 | if((!finite(z))&&finite(x)&&finite(y)) { |
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| 73 | /* hypot(finite,finite) overflow */ |
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| 74 | #ifndef HUGE_VAL |
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| 75 | #define HUGE_VAL inf |
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| 76 | double inf = 0.0; |
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| 77 | |
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| 78 | SET_HIGH_WORD(inf,0x7ff00000); /* set inf to infinite */ |
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| 79 | #endif |
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| 80 | exc.type = OVERFLOW; |
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| 81 | exc.name = "hypot"; |
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| 82 | exc.err = 0; |
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| 83 | exc.arg1 = x; |
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| 84 | exc.arg2 = y; |
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| 85 | if (_LIB_VERSION == _SVID_) |
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| 86 | exc.retval = HUGE; |
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| 87 | else |
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| 88 | exc.retval = HUGE_VAL; |
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| 89 | if (_LIB_VERSION == _POSIX_) |
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| 90 | errno = ERANGE; |
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| 91 | else if (!matherr(&exc)) { |
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| 92 | errno = ERANGE; |
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| 93 | } |
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| 94 | if (exc.err != 0) |
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| 95 | errno = exc.err; |
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| 96 | return exc.retval; |
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| 97 | } else |
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| 98 | return z; |
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| 99 | #endif |
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| 100 | } |
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| 101 | |
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| 102 | #endif /* defined(_DOUBLE_IS_32BITS) */ |
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