FEUPDATEENV(P)                                                                     FEUPDATEENV(P)



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 float-
       ing-point exceptions. The argument envp shall point to an object set by a call to  fehold-
       except() 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  excep-
       tions:


              #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 orig-
       inal Standard can be obtained online at http://www.opengroup.org/unix/online.html .



POSIX                                          2003                                FEUPDATEENV(P)