diff options
Diffstat (limited to 'libm/man/feenableexcept.3')
-rw-r--r-- | libm/man/feenableexcept.3 | 98 |
1 files changed, 98 insertions, 0 deletions
diff --git a/libm/man/feenableexcept.3 b/libm/man/feenableexcept.3 new file mode 100644 index 0000000..0b790e7 --- /dev/null +++ b/libm/man/feenableexcept.3 @@ -0,0 +1,98 @@ +.\" Copyright (c) 2004 David Schultz <das@FreeBSD.org> +.\" All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.\" $FreeBSD: src/lib/msun/man/feenableexcept.3,v 1.1 2005/03/16 19:04:28 das Exp $ +.\" +.Dd March 16, 2005 +.Dt FEENABLEEXCEPT 3 +.Os +.Sh NAME +.Nm feenableexcept , +.Nm fedisableexcept , +.Nm fegetexcept +.Nd floating-point exception masking +.Sh LIBRARY +.Lb libm +.Sh SYNOPSIS +.In fenv.h +.Fd "#pragma STDC FENV_ACCESS ON" +.Ft int +.Fn feenableexcept "int excepts" +.Ft int +.Fn fedisableexcept "int excepts" +.Ft int +.Fn fegetexcept "void" +.Sh DESCRIPTION +The +.Fn feenableexcept +and +.Fn fedisableexcept +functions +unmask and mask (respectively) exceptions specified in +.Fa excepts . +The +.Fn fegetexcept +function +returns the current exception mask. +All exceptions are masked by default. +.Pp +Floating-point operations that produce unmasked exceptions will trap, and a +.Dv SIGFPE +will be delivered to the process. +By installing a signal handler for +.Dv SIGFPE , +applications can take appropriate action immediately without +testing the exception flags after every operation. +Note that the trap may not be immediate, but it should occur +before the next floating-point instruction is executed. +.Pp +For all of these functions, the possible types of exceptions +include those described in +.Xr fenv 3 . +Some architectures may define other types of floating-point exceptions. +.Sh RETURN VALUES +The +.Fn feenableexcept , +.Fn fedisableexcept , +and +.Fn fegetexcept +functions return a bitmap of the exceptions that were unmasked +prior to the call. +.Sh SEE ALSO +.Xr sigaction 2 , +.Xr feclearexcept 3 , +.Xr feholdexcept 3 , +.Xr fenv 3 , +.Xr feupdateenv 3 +.Sh BUGS +Functions in the standard library may trigger exceptions multiple +times as a result of intermediate computations; +however, they generally do not trigger spurious exceptions. +.Pp +No interface is provided to permit exceptions to be handled in +nontrivial ways. +There is no uniform way for an exception handler to access +information about the exception-causing instruction, or +to determine whether that instruction should be reexecuted +after returning from the handler. |