.\" 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
.\" 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, write to the Free
-.\" Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111,
-.\" USA.
+.\" 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 2010-10-31 "Linux" "Linux Programmer's Manual"
+.TH FENV 3 2014-04-01 "Linux" "Linux Programmer's Manual"
.SH NAME
feclearexcept, fegetexceptflag, feraiseexcept, fesetexceptflag,
fetestexcept, fegetenv, fegetround, feholdexcept, fesetround,
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.).
+of floating-point rounding and exceptions (overflow, zero-divide, etc.).
.SS Exceptions
The
.I divide-by-zero
.I invalid
exception occurs when there is no well-defined result
for an operation, as for 0/0 or infinity \- infinity or sqrt(\-1).
-.SS "Exception handling"
+.SS Exception handling
Exceptions are represented in two ways: as a single bit
(exception present/absent), and these bits correspond in some
implementation-defined way with bit positions in an integer,
should reflect the current rounding mode as set by
.BR fesetround ()
(but see BUGS).
-.SS "Floating-point environment"
+.SS Floating-point environment
The entire floating-point environment, including
control modes and status flags, can be handled
as one opaque object, of type
The default environment is denoted by
.B FE_DFL_ENV
(of type
-.IR "const fenv_t *" ).
+.IR "const fenv_t\ *" ).
This is the environment setup at program start and it is defined by
ISO C to have round to nearest, all exceptions cleared and a nonstop
(continue on exceptions) mode.
As before, the object
.I *envp
must be known to be valid.
-.SH "RETURN VALUE"
+.SH RETURN VALUE
These functions return zero on success and nonzero if an error occurred.
.\" Earlier seven of these functions were listed as returning void.
.\" This was corrected in Corrigendum 1 (ISO/IEC 9899:1999/Cor.1:2001(E))
.\" of the C99 Standard.
.SH VERSIONS
These functions first appeared in glibc in version 2.1.
-.SH "CONFORMING TO"
+.SH ATTRIBUTES
+.SS Multithreading (see pthreads(7))
+The
+.BR feclearexcept (),
+.BR fegetexceptflag (),
+.BR fegetexceptflag (),
+.BR fesetexceptflag (),
+.BR fetestexcept (),
+.BR fegetround (),
+.BR fesetround (),
+.BR fegetenv (),
+.BR feholdexcept (),
+.BR fesetenv (),
+.BR feupdateenv (),
+.BR feenableexcept (),
+.BR fedisableexcept (),
+and
+.BR fegetexcept ()
+functions are thread-safe.
+.SH CONFORMING TO
IEC 60559 (IEC 559:1989), ANSI/IEEE 854, C99, POSIX.1-2001.
.SH NOTES
-.SS Glibc Notes
+.SS Glibc notes
If possible, the GNU C Library defines a macro
.B FE_NOMASK_ENV
which represents an environment where every exception raised causes a
trap to occur.
You can test for this macro using
.BR #ifdef .
-It is only defined if
+It is defined only if
.B _GNU_SOURCE
is defined.
The C99 standard does not define a way to set individual bits in the
.B FLT_ROUNDS
always has the value 1.
.\" See http://gcc.gnu.org/ml/gcc/2002-02/msg01535.html
-.SH "SEE ALSO"
+.SH SEE ALSO
.BR math_error (7)
+.SH COLOPHON
+This page is part of release 3.79 of the Linux
+.I man-pages
+project.
+A description of the project,
+information about reporting bugs,
+and the latest version of this page,
+can be found at
+\%http://www.kernel.org/doc/man\-pages/.
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