| The Android Open Source Project | 1dc9e47 | 2009-03-03 19:28:35 -0800 | [diff] [blame] | 1 | .\" Copyright (c) 2004 David Schultz <das@FreeBSD.org> |
| 2 | .\" All rights reserved. |
| 3 | .\" |
| 4 | .\" Redistribution and use in source and binary forms, with or without |
| 5 | .\" modification, are permitted provided that the following conditions |
| 6 | .\" are met: |
| 7 | .\" 1. Redistributions of source code must retain the above copyright |
| 8 | .\" notice, this list of conditions and the following disclaimer. |
| 9 | .\" 2. Redistributions in binary form must reproduce the above copyright |
| 10 | .\" notice, this list of conditions and the following disclaimer in the |
| 11 | .\" documentation and/or other materials provided with the distribution. |
| 12 | .\" |
| 13 | .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND |
| 14 | .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 15 | .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 16 | .\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
| 17 | .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 18 | .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 19 | .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 20 | .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 21 | .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 22 | .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 23 | .\" SUCH DAMAGE. |
| 24 | .\" |
| 25 | .\" $FreeBSD: src/lib/msun/man/feclearexcept.3,v 1.3 2005/01/14 09:12:05 ru Exp $ |
| 26 | .\" |
| 27 | .Dd May 8, 2004 |
| 28 | .Dt FECLEAREXCEPT 3 |
| 29 | .Os |
| 30 | .Sh NAME |
| 31 | .Nm feclearexcept , |
| 32 | .Nm fegetexceptflag , |
| 33 | .Nm feraiseexcept , |
| 34 | .Nm fesetexceptflag , |
| 35 | .Nm fetestexcept |
| 36 | .Nd floating-point exception flag manipulation |
| 37 | .Sh LIBRARY |
| 38 | .Lb libm |
| 39 | .Sh SYNOPSIS |
| 40 | .In fenv.h |
| 41 | .Fd "#pragma STDC FENV_ACCESS ON" |
| 42 | .Ft int |
| 43 | .Fn feclearexcept "int excepts" |
| 44 | .Ft int |
| 45 | .Fn fegetexceptflag "fexcept_t *flagp" "int excepts" |
| 46 | .Ft int |
| 47 | .Fn feraiseexcept "int excepts" |
| 48 | .Ft int |
| 49 | .Fn fesetexceptflag "const fexcept_t *flagp" "int excepts" |
| 50 | .Ft int |
| 51 | .Fn fetestexcept "int excepts" |
| 52 | .Sh DESCRIPTION |
| 53 | The |
| 54 | .Fn feclearexcept |
| 55 | routine clears the floating-point exception flags specified by |
| 56 | .Fa excepts , |
| 57 | whereas |
| 58 | .Fn feraiseexcept |
| 59 | raises the specified exceptions. |
| 60 | Raising an exception causes the corresponding flag to be set, |
| 61 | and a |
| 62 | .Dv SIGFPE |
| 63 | is delivered to the process if the exception is unmasked. |
| 64 | .Pp |
| 65 | The |
| 66 | .Fn fetestexcept |
| 67 | function determines which flags are currently set, of those specified by |
| 68 | .Fa excepts . |
| 69 | .Pp |
| 70 | The |
| 71 | .Fn fegetexceptflag |
| 72 | function stores the state of the exception flags specified in |
| 73 | .Fa excepts |
| 74 | in the opaque object pointed to by |
| 75 | .Fa flagp . |
| 76 | Similarly, |
| 77 | .Fn fesetexceptflag |
| 78 | changes the specified exception flags to reflect the state stored in |
| 79 | the object pointed to by |
| 80 | .Fa flagp . |
| 81 | Note that the flags restored with |
| 82 | .Fn fesetexceptflag |
| 83 | must be a (not necessarily proper) subset of the flags recorded by |
| 84 | a prior call to |
| 85 | .Fn fegetexceptflag . |
| 86 | .Pp |
| 87 | For all of these functions, the possible types of exceptions |
| 88 | include those described in |
| 89 | .Xr fenv 3 . |
| 90 | Some architectures may define other types of floating-point exceptions. |
| 91 | .Sh IMPLEMENTATION NOTES |
| 92 | On some architectures, raising an overflow or underflow exception |
| 93 | also causes an inexact exception to be raised. |
| 94 | In these cases, the overflow or underflow will be raised first. |
| 95 | .Pp |
| 96 | The |
| 97 | .Fn fegetexceptflag |
| 98 | and |
| 99 | .Fn fesetexceptflag |
| 100 | routines are preferred to |
| 101 | .Fn fetestexcept |
| 102 | and |
| 103 | .Fn feraiseexcept , |
| 104 | respectively, for saving and restoring exception flags. |
| 105 | The latter do not re-raise exceptions and may preserve |
| 106 | architecture-specific information such as addresses where |
| 107 | exceptions occurred. |
| 108 | .Sh RETURN VALUES |
| 109 | The |
| 110 | .Fn feclearexcept , |
| 111 | .Fn fegetexceptflag , |
| 112 | .Fn feraiseexcept , |
| 113 | and |
| 114 | .Fn fesetexceptflag |
| 115 | functions return 0 upon success, and non-zero otherwise. |
| 116 | The |
| 117 | .Fn fetestexcept |
| 118 | function returns the bitwise OR of the values of the current exception |
| 119 | flags that were requested. |
| 120 | .Sh SEE ALSO |
| 121 | .Xr sigaction 2 , |
| 122 | .Xr feholdexcept 3 , |
| 123 | .Xr fenv 3 , |
| 124 | .Xr feupdateenv 3 , |
| 125 | .Xr fpgetsticky 3 , |
| 126 | .Xr fpresetsticky 3 |
| 127 | .Sh STANDARDS |
| 128 | The |
| 129 | .Fn feclearexcept , |
| 130 | .Fn fegetexceptflag , |
| 131 | .Fn feraiseexcept , |
| 132 | .Fn fesetexceptflag , |
| 133 | and |
| 134 | .Fn fetestexcept |
| 135 | routines conform to |
| 136 | .St -isoC-99 . |
| 137 | .Sh HISTORY |
| 138 | These functions first appeared in |
| 139 | .Fx 5.3 . |