fesetflushtozero(3m) [hpux man page]

fesetflushtozero(3M)													      fesetflushtozero(3M)

NAME

       fesetflushtozero() - set floating-point underflow mode

SYNOPSIS

DESCRIPTION

       The  function  sets the current underflow mode.	If the argument is 1, the underflow mode is set to flush-to-zero mode.	If the argument is
       zero, the underflow mode is set to IEEE-754-compliant (gradual) underflow mode.	For arguments other than 1 or zero, the  effect  is  unde-
       fined.

       The default underflow mode is IEEE-754-compliant.

       Flush-to-zero  mode,  also  known as fast underflow mode, is supported on most PA1.1 systems and on all PA2.0 and HP Integrity servers.	In
       IEEE-754-compliant mode, cases that might underflow may be handled by trapping into the kernel, where the IEEE-mandated conversion  of  the
       result into a denormalized value or zero is accomplished by software emulation.

       On PA-RISC systems, flush-to-zero mode allows the substitution of a zero for denormal operands and operation results, without trapping into
       the kernel.

       On Integrity servers, flush-to-zero mode causes a zero to be substituted for denormal results (but not operands), without trapping into the
       kernel.

       Flush-to-zero mode may offer a significant performance improvement for some applications.

USAGE

       To use this function, compile either with the default option or with the and options.  Make sure your program includes

       For Integrity servers, specify on the compiler command line or place the call to this function under the effect of an affirmative pragma:

       If  the pragma is placed outside of any top-level declarations in a file, the pragma will apply to all declarations in the compilation fol-
       lowing the pragma until another pragma is encountered or until the end of the file is reached.

       If the pragma is placed at the beginning of a block (compound statement), the pragma will apply until  another  pragma  is  encountered	or
       until the end of the block is reached.

       For  PA-RISC, you might need to use the compiler option in order to prevent optimizations that can undermine the specified behavior of this
       function.

       Link in the math library by specifying on the compiler or linker command line.

       For more information, see the at the following site:

RETURN VALUE

       None.

ERRORS

       No errors are defined.

EXAMPLES

       Save the current underflow mode, set flush-to-zero mode, and restore the previous mode.

AUTHOR

       was developed by HP and is not required by any current standard.

SEE ALSO

       fegetflushtozero(3M), fenv(5).

															      fesetflushtozero(3M)

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feupdateenv(3M) 														   feupdateenv(3M)

NAME

       feupdateenv() - update floating-point environment

SYNOPSIS

   HP Integrity Server Only
   PA-RISC Only
DESCRIPTION

       The  function saves the currently raised floating-point exceptions in its automatic storage, installs the floating-point environment repre-
       sented by the object pointed to by envp, and then raises the saved floating-point exceptions.  Use with	to  hide  spurious  floating-point
       exceptions.

       The argument envp must point to an object set by a call to or or equal the macro

USAGE

       To use this function, compile either with the default option or with the and options.  Make sure your program includes

       For Integrity servers, specify on the compiler command line or place the call to this function under the effect of an affirmative pragma:

       If  the pragma is placed outside of any top-level declarations in a file, the pragma will apply to all declarations in the compilation fol-
       lowing the pragma until another pragma is encountered or until the end of the file is reached.

       If the pragma is placed at the beginning of a block (compound statement), the pragma will apply until  another  pragma  is  encountered	or
       until the end of the block is reached.

       For  PA-RISC, you might need to use the compiler option in order to prevent optimizations that can undermine the specified behavior of this
       function.

       Link in the math library by specifying on the compiler or linker command line.

       For more information, see the at the following site:

RETURN VALUE

   Integrity Server Only
       This function always returns 0, indicating that all the actions were successfully carried out.

   PA-RISC Only
       None.

ERRORS

       No errors are defined.

EXAMPLES

       Store the current floating-point environment in hide spurious underflow exceptions, and continue  on  any  floating-point  exceptions  that
       occur until the call to is encountered.

SEE ALSO

       fegetenv(3M), feholdexcept(3M), fesetenv(3M), fenv(5).

STANDARDS CONFORMANCE

       : ISO/IEC C99 (including Annex F, "IEC 60559 floating-point arithmetic")

																   feupdateenv(3M)

Linux and UNIX Man Pages

fesetflushtozero(3m) [hpux man page]

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