std::is_string_literal

 

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Checking string literals is_string_literal Helper types info tuple_size tuple_element is_applicable_type is_nothrow_applicable_type      apply_result variant_size variant_alternative type_order exception Promoting to static storage reflect_constant_string reflect_constant_array define_static_string define_static_array define_static_object Operator representations operators operator_of symbol_of u8symbol_of Names and locations has_identifier identifier_of u8identifier_of display_string_of u8display_string_of source_location_of Reflection queries ➜ Access control context access_context

Member accessibility queries is_accessible has_inaccessible_nonstatic_   data_members has_inaccessible_bases has_inaccessible_subobjects      Scope identification current_function current_class current_namespace Reflection member queries members_of bases_of static_data_members_of nonstatic_data_members_of subobjects_of enumerators_of Annotation reflection annotations_of annotations_of_with_type Value extraction extract Reflection substitution reflection_range can_substitute substitute Expression result reflection reflect_constant reflect_object reflect_function Class definition generation data_member_options data_member_spec is_data_member_spec define_aggregate

Primary type categories is_void_type is_null_pointer_type is_integral_type is_floating_point_type is_array_type is_pointer_type is_lvalue_reference_type is_rvalue_reference_type is_member_object_pointer_type is_member_function_pointer_type      is_enum_type is_union_type is_class_type is_function_type is_reflection_type Composite type categories is_reference_type is_arithmetic_type is_fundamental_type is_object_type is_scalar_type is_compound_type is_member_pointer_type Type properties ➜ Type relations is_same_type is_base_of_type is_virtual_base_of_type is_convertible_type is_nothrow_convertible_type is_layout_compatible_type is_pointer_interconvertible_   base_of_type is_invocable_type is_invocable_r_type is_nothrow_invocable_type is_nothrow_invocable_r_type

Const-volatile modifications remove_const remove_volatile remove_cv add_const add_volatile add_cv Reference modifications remove_reference add_lvalue_reference add_rvalue_reference Sign modifications make_signed make_unsigned Array modifications remove_extent remove_all_extents Pointer modifications remove_pointer add_pointer Other transformations remove_cvref decay common_type common_reference underlying_type invoke_result unwrap_reference unwrap_ref_decay

 

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Reflection queries type_of object_of constant_of is_public is_protected is_private is_virtual is_pure_virtual is_override is_final is_deleted is_defaulted is_user_provided is_user_declared is_explicit is_noexcept is_bit_field is_enumerator is_annotation is_const is_volatile is_mutable_member is_lvalue_reference_qualified is_rvalue_reference_qualified has_static_storage_duration has_thread_storage_duration has_automatic_storage_duration      has_internal_linkage has_module_linkage has_external_linkage has_c_language_linkage has_linkage is_complete_type is_enumerable_type is_variable is_type is_namespace is_type_alias is_namespace_alias is_function is_conversion_function is_operator_function is_literal_operator is_special_member_function is_constructor is_default_constructor is_copy_constructor

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is_standard_layout_type is_empty_type is_polymorphic_type is_abstract_type is_final_type is_aggregate_type is_structural_type is_signed_type is_unsigned_type is_bounded_array_type is_unbounded_array_type is_scoped_enum_type is_constructible_type is_default_constructible_type is_copy_constructible_type is_move_constructible_type is_assignable_type is_copy_assignable_type is_move_assignable_type is_swappable_with_type is_swappable_type is_destructible_type is_trivially_constructible_type is_trivially_default_constructible_type is_trivially_copy_constructible_type is_trivially_move_constructible_type is_trivially_assignable_type is_trivially_copy_assignable_type is_trivially_move_assignable_type is_trivially_destructible_type is_nothrow_constructible_type is_nothrow_default_constructible_type is_nothrow_copy_constructible_type is_nothrow_move_constructible_type is_nothrow_assignable_type is_nothrow_copy_assignable_type is_nothrow_move_assignable_type is_nothrow_swappable_with_type is_nothrow_swappable_type is_nothrow_destructible_type is_implicit_lifetime_type has_virtual_destructor has_unique_object_representations reference_constructs_from_temporary reference_converts_from_temporary Type property queries rank extent

 

Defined in header <meta>
consteval bool is_string_literal( const char* p );	(1)	(since C++26)
consteval bool is_string_literal( const wchar_t* p );	(2)	(since C++26)
consteval bool is_string_literal( const char8_t* p );	(3)	(since C++26)
consteval bool is_string_literal( const char16_t* p );	(4)	(since C++26)
consteval bool is_string_literal( const char32_t* p );	(5)	(since C++26)

Determines if p points to an element of a string literal object.

The result is determined as follows:

• If p points to an object that is not usable in constant expressions, returns false.
• Otherwise, if p points to a subobject of a string literal object, returns true.
• Otherwise, returns false.

Parameters

p

-

a character pointer

Return value

true if p is statically determined to point into a string literal, false otherwise.

Example

Run this code

#include <meta>

int main()
{
    constexpr const char* p = "";
    constexpr const char a[] = "";

    static_assert(std::is_string_literal(p));
    static_assert(!std::is_string_literal(a));
    static_assert(std::is_string_literal(LR"(wcahr_t)"));
    static_assert(std::is_string_literal(R"(\N{CAT})"));
}

See also

define_static_string (C++26)

promotes compile-time string to static storage, returning a pointer to the first character of the static string (function template)