std::fegetenv, std::fesetenv

 

C++

Language

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Named requirements

Language support library

Concepts library (C++20)

Diagnostics library

Utilities library

Strings library

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Ranges library (C++20)

Algorithms library

Numerics library

Input/output library

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Regular expressions library (C++11)

Atomic operations library (C++11)

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Technical Specifications

 

Numerics library

Common mathematical functions

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Floating-point environment (C++11)

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Compile-time rational arithmetic (C++11)

Numeric algorithms

gcd (C++17)

lcm (C++17)

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midpoint (C++20)

lerp (C++20)

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iota (C++11)

accumulate

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reduce (C++17)

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inclusive_scan (C++17)

exclusive_scan (C++17)

transform_inclusive_scan (C++17)

transform_exclusive_scan (C++17)

Bit operations

bit_cast (C++20)

ispow2 (C++20)

ceil2 (C++20)

floor2 (C++20)

log2p1 (C++20)

 

Floating-point environment

Functions

feclearexcept (C++11)

fetestexcept (C++11)

feraiseexcept (C++11)

fegetexceptflagfesetexceptflag (C++11)(C++11)

fegetroundfesetround (C++11)(C++11)

fegetenvfesetenv (C++11)

feholdexcept (C++11)

feupdateenv (C++11)

Macro constants

FE_ALL_EXCEPTFE_DIVBYZEROFE_INEXACTFE_INVALIDFE_OVERFLOWFE_UNDERFLOW (C++11)

FE_DOWNWARDFE_TONEARESTFE_TOWARDZEROFE_UPWARD (C++11)

FE_DFL_ENV (C++11)

 

Defined in header <cfenv>
int fegetenv( std::fenv_t* envp )	(1)	(since C++11)
int fesetenv( const std::fenv_t* envp );	(2)	(since C++11)

Manages the status of the floating-point environment.

1) Attempts to store the status of the floating-point environment in the object pointed to by envp.

2) Attempts to establish the floating-point environment from the object pointed to by envp. The value of that object must be previously obtained by a call to std::feholdexcept or std::fegetenv or be a floating-point macro constant. If any of the floating-point status flags are set in envp, they become set in the environment (and are then testable with std::fetestexcept), but the corresponding floating-point exceptions are not raised (execution continues uninterrupted)

Parameters

envp

-

pointer to the object of type std::fenv_t which holds the status of the floating-point environment

Return value

​0​ on success, non-zero otherwise.

See also

feholdexcept (C++11)	saves the environment, clears all status flags and ignores all future errors (function)
feupdateenv (C++11)	restores the floating-point environment and raises the previously raise exceptions (function)
FE_DFL_ENV (C++11)	default floating-point environment (macro constant)