fuse.4: ffix

[thirdparty/man-pages.git] / man3 / fenv.3

.\" Copyright (c) 2000 Andries Brouwer (aeb@cwi.nl)
.\"
.\" %%%LICENSE_START(GPLv2+_DOC_FULL)
.\" This is free documentation; you can redistribute it and/or
.\" modify it under the terms of the GNU General Public License as
.\" published by the Free Software Foundation; either version 2 of
.\" the License, or (at your option) any later version.
.\"
.\" The GNU General Public License's references to "object code"
.\" and "executables" are to be interpreted as the output of any
.\" document formatting or typesetting system, including
.\" intermediate and printed output.
.\"
.\" This manual is distributed in the hope that it will be useful,
.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
.\" GNU General Public License for more details.
.\"
.\" You should have received a copy of the GNU General Public
.\" License along with this manual; if not, see
.\" <http://www.gnu.org/licenses/>.
.\" %%%LICENSE_END
.\"
.\" 2000-08-14 added GNU additions from Andreas Jaeger
.\" 2000-12-05 some changes inspired by acahalan's remarks
.\"
.TH FENV 3  2015-03-02 "Linux" "Linux Programmer's Manual"
.SH NAME
feclearexcept, fegetexceptflag, feraiseexcept, fesetexceptflag,
fetestexcept, fegetenv, fegetround, feholdexcept, fesetround,
fesetenv, feupdateenv, feenableexcept, fedisableexcept,
fegetexcept \- floating-point rounding and exception handling
.SH SYNOPSIS
.nf
.B #include <fenv.h>
.sp
.BI "int feclearexcept(int " excepts );
.br
.BI "int fegetexceptflag(fexcept_t *" flagp ", int " excepts );
.br
.BI "int feraiseexcept(int " excepts );
.br
.BI "int fesetexceptflag(const fexcept_t *" flagp ", int " excepts );
.br
.BI "int fetestexcept(int " excepts );
.sp
.B "int fegetround(void);"
.br
.BI "int fesetround(int " rounding_mode );
.sp
.BI "int fegetenv(fenv_t *" envp );
.br
.BI "int feholdexcept(fenv_t *" envp );
.br
.BI "int fesetenv(const fenv_t *" envp );
.br
.BI "int feupdateenv(const fenv_t *" envp );
.fi
.sp
Link with \fI\-lm\fP.
.SH DESCRIPTION
These eleven functions were defined in C99, and describe the handling
of floating-point rounding and exceptions (overflow, zero-divide, etc.).
.SS Exceptions
The
.I divide-by-zero
exception occurs when an operation on finite numbers
produces infinity as exact answer.
.LP
The
.I overflow
exception occurs when a result has to be represented as a
floating-point number, but has (much) larger absolute value than the
largest (finite) floating-point number that is representable.
.LP
The
.I underflow
exception occurs when a result has to be represented as a
floating-point number, but has smaller absolute value than the smallest
positive normalized floating-point number (and would lose much accuracy
when represented as a denormalized number).
.LP
The
.I inexact
exception occurs when the rounded result of an operation
is not equal to the infinite precision result.