FLT_ROUNDS

 

C++

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Technical Specifications

 

Utilities library

Type support (basic types, RTTI, type traits)
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rel_ops::operator!=rel_ops::operator>rel_ops::operator<=rel_ops::operator>=
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strong_order weak_order partial_order strong_equal weak_equal	strong_ordering weak_ordering partial_ordering strong_equality weak_equality	is_eqis_neqis_ltis_lteqis_gtis_gteq
common_comparison_category
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pair tuple (C++11) apply (C++17) make_from_tuple (C++17)	optional (C++17) any (C++17) variant (C++17)
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swap
exchange (C++14)
forward (C++11)
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declval (C++11)
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ptrdiff_t size_t max_align_t (C++11) byte (C++17)	nullptr_t (C++11) offsetof NULL
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C numeric limits interface
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is_reference (C++11)
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negation (C++17)
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endian (C++20)
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Supported operations
is_constructibleis_trivially_constructibleis_nothrow_constructible (C++11)(C++11)(C++11)
is_default_constructibleis_trivially_default_constructibleis_nothrow_default_constructible (C++11)(C++11)(C++11)
is_copy_constructibleis_trivially_copy_constructibleis_nothrow_copy_constructible (C++11)(C++11)(C++11)
is_move_constructibleis_trivially_move_constructibleis_nothrow_move_constructible (C++11)(C++11)(C++11)
is_assignableis_trivially_assignableis_nothrow_assignable (C++11)(C++11)(C++11)
is_copy_assignableis_trivially_copy_assignableis_nothrow_copy_assignable (C++11)(C++11)(C++11)
is_move_assignableis_trivially_move_assignableis_nothrow_move_assignable (C++11)(C++11)(C++11)
is_destructibleis_trivially_destructibleis_nothrow_destructible (C++11)(C++11)(C++11)
has_virtual_destructor (C++11)
is_swappable_withis_swappableis_nothrow_swappable_withis_nothrow_swappable (C++17)(C++17)(C++17)(C++17)
Relationships and property queries
is_same (C++11) is_base_of (C++11) is_convertibleis_nothrow_convertible (C++11)(C++20)	alignment_of (C++11) rank (C++11) extent (C++11)
is_invocableis_invocable_ris_nothrow_invocableis_nothrow_invocable_r (C++17)(C++17)(C++17)(C++17)
Type modifications
remove_cvremove_constremove_volatile (C++11)(C++11)(C++11) add_cvadd_constadd_volatile (C++11)(C++11)(C++11) make_signed (C++11) make_unsigned (C++11)	remove_reference (C++11) add_lvalue_referenceadd_rvalue_reference (C++11)(C++11) remove_pointer (C++11) add_pointer (C++11) remove_extent (C++11) remove_all_extents (C++11)
Type transformations
aligned_storage (C++11) aligned_union (C++11) decay (C++11) remove_cvref (C++20) enable_if (C++11) void_t (C++17)	conditional (C++11) common_type (C++11) common_reference (C++20) underlying_type (C++11) result_ofinvoke_result (C++11)(until C++20)(C++17) type_identity (C++20)

 

C numeric limits interface

FLT_ROUNDS

FLT_EVAL_METHOD (C++11)

 

Defined in header <cfloat>
#define FLT_ROUNDS /* implementation defined */

Specifies the current rounding direction of floating-point arithmetic operations.

Value	Explanation
-1	the default rounding direction is not known
0	toward zero; same meaning as FE_TOWARDZERO
1	to nearest; same meaning as FE_TONEAREST
2	towards positive infinity; same meaning as FE_UPWARD
3	towards negative infinity; same meaning as FE_DOWNWARD
other values	implementation-defined behavior

Notes

The rounding mode can be changed with std::fesetround and FLT_ROUNDS reflects that change.

The possible values of FLT_ROUNDS match the possible values of std::float_round_style, returned by std::numeric_limits::round_style.

See also

float_round_style	indicates floating-point rounding modes (enum)
fegetroundfesetround (C++11)(C++11)	gets or sets rounding direction (function)
FE_DOWNWARDFE_TONEARESTFE_TOWARDZEROFE_UPWARD (C++11)	floating-point rounding direction (macro constant)