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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fesetexceptflag(3M)													       fesetexceptflag(3M)

NAME

       fesetexceptflag() - set floating-point exception flags

SYNOPSIS

   HP Integrity Server Only
   PA-RISC Only
DESCRIPTION

       The  function  sets  the status for the floating-point exception flags indicated by the argument excepts to the states stored in the object
       pointed to by flagp.  The value of *flagp must have been set by a previous call to whose second argument represented at least those  float-
       ing-point  exceptions  represented  by the argument excepts; otherwise, the effect on the indicated floating-point exception flags is unde-
       fined.  This function does not raise exceptions, but only sets the state of the flags (hence no traps will be taken).  The excepts argument
       can be constructed as a bitwise OR of the floating-point exception macros: and represents all the floating-point exceptions.

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 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 specified flags were successfully set to the appropriate state.

   PA-RISC Only
       None.

ERRORS

       No errors are defined.

EXAMPLES

       Use to save the current state of two floating-point exception flags.  Later, use to restore the saved state.

SEE ALSO

       feclearexcept(3M), fegetexceptflag(3M), fegettrapenable(3M), feraiseexcept(3M), fesettrapenable(3M), fetestexcept(3M), fenv(5).

STANDARDS CONFORMANCE

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

															       fesetexceptflag(3M)

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fesetflushtozero(3m) [hpux man page]

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