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HP-UX Reference > Ffenv(5)HP-UX 11i Version 2: December 2007 Update |
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NAMEfenv — floating-point environment macros and functions DESCRIPTIONThe 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 (but never cleared) when a floating-point exception is raised, which occurs as a side effect of exceptional floating-point 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 floating-point arithmetic; on HP 9000 and Itanium(R)-based systems the control modes include the rounding direction mode, the gradual/flush-to-zero underflow mode, and the trap enables. The following types are defined:
The following macros represent the floating-point status flags. They are defined as integral constant expressions with values such that bitwise ORs of all combinations of the macros result in distinct values.
The following macros represent the rounding direction modes. They are defined as integral constant expressions with distinct nonnegative values.
The following macro is defined as a pointer to const-qualified fenv_t:
To the ISO/IEC C99 specified facilities, the HP implementation adds four HP-specific functions: fegetflushtozero(), fesetflushtozero(), fegettrapenable(), and fesettrapenable(). |
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