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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 dif-
       fer (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 auto-
       matic 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.

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, Stan-
       dard 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)