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FEUPDATEENV(3P) POSIX Programmer's Manual FEUPDATEENV(3P)
This manual page is part of the POSIX Programmer's Manual. The Linux
implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior), or
the interface may not be implemented on Linux.
feupdateenv — update floating-point environment
#include <fenv.h>
int feupdateenv(const fenv_t *envp);
The functionality described on this reference page is aligned with
the ISO C standard. Any conflict between the requirements described
here and the ISO C standard is unintentional. This volume of
POSIX.1‐2008 defers to the ISO C standard.
The feupdateenv() function shall attempt to save the currently raised
floating-point exceptions in its automatic storage, attempt to
install the floating-point environment represented by the object
pointed to by envp, and then attempt to raise the saved floating-
point exceptions. The argument envp shall point to an object set by a
call to feholdexcept() or fegetenv(), or equal a floating-point
environment macro.
The feupdateenv() function shall return a zero value if and only if
all the required actions were successfully carried out.
No errors are defined.
The following sections are informative.
The following example shows sample code to hide spurious underflow
floating-point exceptions:
#include <fenv.h>
double f(double x)
{
#pragma STDC FENV_ACCESS ON
double result;
fenv_t save_env;
feholdexcept(&save_env);
// compute result
if (/* test spurious underflow */)
feclearexcept(FE_UNDERFLOW);
feupdateenv(&save_env);
return result;
}
None.
None.
None.
fegetenv(3p), feholdexcept(3p)
The Base Definitions volume of POSIX.1‐2008, fenv.h(0p)
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The Open
Group Base Specifications Issue 7, Copyright (C) 2013 by the
Institute of Electrical and Electronics Engineers, Inc and The Open
Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
applied.) In the event of any discrepancy between this version and
the original IEEE and The Open Group Standard, the original IEEE and
The Open Group Standard is the referee document. The original
Standard can be obtained online at http://www.unix.org/online.html .
Any typographical or formatting errors that appear in this page are
most likely to have been introduced during the conversion of the
source files to man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group 2013 FEUPDATEENV(3P)
Pages that refer to this page: fenv.h(0p), fegetenv(3p), feholdexcept(3p)