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FEUPDATEENV(3P)            POSIX Programmer's Manual           FEUPDATEENV(3P)

PROLOG
       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.
NAME
       feupdateenv - update floating-point environment
SYNOPSIS
       #include <fenv.h>
       int feupdateenv(const fenv_t *envp);

DESCRIPTION
       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  feholdex-
       cept() or fegetenv(), or equal a floating-point environment macro.
RETURN VALUE
       The feupdateenv() function shall return a zero value if and only if all
       the required actions were successfully carried out.
ERRORS
       No errors are defined.
       The following sections are informative.
EXAMPLES
       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;
              }
APPLICATION USAGE
       None.
RATIONALE
       None.
FUTURE DIRECTIONS
       None.
SEE ALSO
       fegetenv(),    feholdexcept(),   the   Base   Definitions   volume   of
       IEEE Std 1003.1-2001, <fenv.h>
COPYRIGHT
       Portions of this text are reprinted and reproduced in  electronic  form
       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
       -- Portable Operating System Interface (POSIX),  The  Open  Group  Base
       Specifications  Issue  6,  Copyright  (C) 2001-2003 by the Institute of
       Electrical and Electronics Engineers, Inc and The Open  Group.  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.opengroup.org/unix/online.html .

IEEE/The Open Group                  2003                      FEUPDATEENV(3P)