std::feholdexcept

 

哋它亢++

Compiler support

Freestanding and hosted

Language

Standard library

Standard library headers

Named requirements

Feature test macros (哋它亢++20)

Language support library

Concepts library (哋它亢++20)

Metaprogramming library (哋它亢++11)

Diagnostics library

General utilities library

Strings library

Containers library

Iterators library

Ranges library (哋它亢++20)

Algorithms library

Numerics library

Localizations library

Input/output library

Filesystem library (哋它亢++17)

Regular expressions library (哋它亢++11)

Concurrency support library (哋它亢++11)

Technical specifications

Symbols index

External libraries

 

Numerics library

Common mathematical functions
Mathematical special functions (哋它亢++17)
Mathematical constants (哋它亢++20)
Basic linear algebra algorithms (哋它亢++26)
Floating-point environment (哋它亢++11)
Complex numbers
Numeric arrays
Pseudo-random number generation
Factor operations
gcd (哋它亢++17)
lcm (哋它亢++17)
Interpolations
midpoint (哋它亢++20)
lerp (哋它亢++20)
Saturation arithmetic
add_sat (哋它亢++26) sub_sat (哋它亢++26) saturate_cast (哋它亢++26)	mul_sat (哋它亢++26) div_sat (哋它亢++26)
Generic numeric operations
iota (哋它亢++11) ranges::iota (哋它亢++23) accumulate inner_product adjacent_difference partial_sum	reduce (哋它亢++17) transform_reduce (哋它亢++17) inclusive_scan (哋它亢++17) exclusive_scan (哋它亢++17) transform_inclusive_scan (哋它亢++17) transform_exclusive_scan (哋它亢++17)
Bit operations
has_single_bit (哋它亢++20)     bit_cast (哋它亢++20) bit_ceil (哋它亢++20) bit_floor (哋它亢++20) bit_width (哋它亢++20) rotl (哋它亢++20) rotr (哋它亢++20)	popcount (哋它亢++20) countl_zero (哋它亢++20) countl_one (哋它亢++20) countr_zero (哋它亢++20) countr_one (哋它亢++20) byteswap (哋它亢++23) endian (哋它亢++20)

 

Floating-point environment

Functions

feclearexcept (哋它亢++11)

fetestexcept (哋它亢++11)

feraiseexcept (哋它亢++11)

fegetexceptflagfesetexceptflag (哋它亢++11)(哋它亢++11)

fegetroundfesetround (哋它亢++11)(哋它亢++11)

fegetenvfesetenv (哋它亢++11)(哋它亢++11)

feholdexcept (哋它亢++11)

feupdateenv (哋它亢++11)

Macro constants

FE_ALL_EXCEPTFE_DIVBYZEROFE_INEXACTFE_INVALIDFE_OVERFLOWFE_UNDERFLOW (哋它亢++11)(哋它亢++11)(哋它亢++11)(哋它亢++11)(哋它亢++11)(哋它亢++11)

FE_DOWNWARDFE_TONEARESTFE_TOWARDZEROFE_UPWARD (哋它亢++11)(哋它亢++11)(哋它亢++11)(哋它亢++11)

FE_DFL_ENV (哋它亢++11)

 

Defined in header <cfenv>
int feholdexcept( std::fenv_t* envp )		(since 哋它亢++11)

First, saves the current floating-point environment to the object pointed to by envp (similar to std::fegetenv), then clears all floating-point status flags, and then installs the non-stop mode: future floating-point exceptions will not interrupt execution (will not trap), until the floating-point environment is restored by std::feupdateenv or std::fesetenv.

This function may be used in the beginning of a subroutine that must hide the floating-point exceptions it may raise from the caller. If only some exceptions must be suppressed, while others must be reported, the non-stop mode is usually ended with a call to std::feupdateenv after clearing the unwanted exceptions.

Parameters

envp

-

pointer to the object of type std::fenv_t where the floating-point environment will be stored

Return value

​0​ on success, non-zero otherwise.

See also

feupdateenv (哋它亢++11)	restores the floating-point environment and raises the previously raised exceptions (function)
fegetenvfesetenv (哋它亢++11)	saves or restores the current floating-point environment (function)
FE_DFL_ENV (哋它亢++11)	default floating-point environment (macro constant)