HP-UX Reference (11i v1 00/12) - 5 Miscellaneous Topics, 7 Device (Special) Files, 9 General Information, Index (vol 9)

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STANDARD Printed by: Nora Chuang [nchuang] STANDARD
/build/1111/BRICK/man5/!!!intro.5
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f
fenv(5) fenv(5)
NAME
fenv - floating-point environment macros and functions
SYNOPSIS
#include <fenv.h>
DESCRIPTION
The header <fenv.h> declares two types and several macros and functions to provide access to the
floating-point environment. The floating-point environment refers collectively to the floating-point status
flags and control modes. A floating-point status flag is a system variable whose value is set as a side effect
of the arithmetic to provide auxiliary information. A floating-point control mode is a system variable whose
value may be set by the user to affect the subsequent behavior of the arithmetic; on HP 9000 systems the
control modes include the rounding direction mode, the underflow mode, and the trap enables.
The following types are defined:
fenv_t Represents the entire floating-point environment.
fexcept_t Represents the floating-point exception flags collectively.
The following macros represent the floating-point status flags. They are defined as integral constant
expressions.
FE_INEXACT The inexact exception.
FE_DIVBYZERO The division-by-zero exception.
FE_UNDERFLOW The underflow exception.
FE_OVERFLOW The overflow exception.
FE_INVALID The invalid operation exception.
FE_ALL_EXCEPT The bitwise OR of all exception macros.
The following macros represent the rounding direction modes. They are defined as integral constant
expressions.
FE_TONEAREST The round-to-nearest rounding direction mode.
FE_UPWARD The round-toward-positive-infinity rounding direction mode.
FE_DOWNWARD The round-toward-negative-infinity rounding direction mode.
FE_TOWARDZERO The round-toward-zero rounding direction mode.
The following macro is defined as a pointer to const-qualified fenv_t:
FE_DFL_ENV The default floating-point environment.
The <fenv.h> header file and its contents have been approved for inclusion in the C9X standard. The HP
implementation adds four HP-specific functions to the approved contents: fegetflushtozero(),
fesetflushtozero(), fegettrapenable(), and fesettrapenable().
FILES
/usr/include/fenv.h
SEE ALSO
feclearexcept(3M), fegetexceptflag(3M), feraiseexcept(3M), fesetexceptflag(3M), fetestexcept(3M),
fegetround(3M), fesetround(3M), fegetenv(3M), feholdexcept(3M), fesetenv(3M), feupdateenv(3M),
fegetflushtozero(3M), fesetflushtozero(3M), fegettrapenable(3M), fesettrapenable(3M).
HP-UX Release 11i: December 2000 − 1 − Section 5−−53
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