diff options
Diffstat (limited to 'lib/msun/man/fegetenv.3')
-rw-r--r-- | lib/msun/man/fegetenv.3 | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/lib/msun/man/fegetenv.3 b/lib/msun/man/fegetenv.3 new file mode 100644 index 0000000..c99663e --- /dev/null +++ b/lib/msun/man/fegetenv.3 @@ -0,0 +1,113 @@ +.\" 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. +.\" +.\" $FreeBSD$ +.\" +.Dd May 8, 2004 +.Dt FEGETENV 3 +.Os +.Sh NAME +.Nm fegetenv , +.Nm feholdexcept , +.Nm fesetenv , +.Nm feupdateenv +.Nd floating-point environment save and restore +.Sh LIBRARY +.Lb libm +.Sh SYNOPSIS +.In fenv.h +.Fd "#pragma STDC FENV_ACCESS ON" +.Ft int +.Fn fegetenv "fenv_t *envp" +.Ft int +.Fn feholdexcept "fenv_t *envp" +.Ft int +.Fn fesetenv "const fenv_t *envp" +.Ft int +.Fn feupdateenv "const fenv_t *envp" +.Sh DESCRIPTION +The floating-point environment includes exception flags and masks, the +current rounding mode, and other architecture-specific settings. +However, it does not include the floating-point register file. +.Pp +The +.Fn fegetenv +function stores the current floating-point environment in the object +pointed to by +.Fa envp , +whereas +.Fn feholdexcept +saves the current environment, then clears all exception flags +and masks all floating-point exceptions. +.Pp +The +.Fn fesetenv +function restores a previously saved environment. +The +.Fn feupdateenv +function restores a saved environment as well, but it also +raises any exceptions that were set in the environment it +replaces. +.Pp +The +.Fn feholdexcept +function is often used with +.Fn feupdateenv +or +.Fn fesetenv +to suppress spurious exceptions that occur as a result of +intermediate computations. +An example in +.Xr fenv 3 +demonstrates how to do this. +.Sh RETURN VALUES +The +.Fn fegetenv , +.Fn feholdexcept , +.Fn fesetenv , +and +.Fn feupdateenv +functions return 0 if they succeed, and non-zero otherwise. +.Sh SEE ALSO +.Xr feclearexcept 3 , +.Xr fenv 3 , +.Xr feraiseexcept 3 , +.Xr fesetenv 3 , +.Xr fetestexcept 3 , +.Xr fpgetmask 3 , +.Xr fpgetprec 3 , +.Xr fpsetmask 3 , +.Xr fpsetprec 3 +.Sh STANDARDS +The +.Fn fegetenv , +.Fn feholdexcept , +.Fn fesetenv , +and +.Fn feupdateenv +functions conform to +.St -isoC-99 . +.Sh HISTORY +These routines first appeared in +.Fx 5.3 . |