#include <bslstl_function.h>
Public Types | |
| typedef Function_Rep::allocator_type | allocator_type |
Public Member Functions | |
| BSLMF_NESTED_TRAIT_DECLARATION (function, BloombergLP::bslma::UsesBslmaAllocator) | |
| BSLMF_NESTED_TRAIT_DECLARATION (function, BloombergLP::bslmf::UsesAllocatorArgT) | |
| BSLMF_NESTED_TRAIT_DECLARATION (function, bsl::is_nothrow_move_constructible) | |
| function () BSLS_KEYWORD_NOEXCEPT | |
| function (nullptr_t) BSLS_KEYWORD_NOEXCEPT | |
| function (allocator_arg_t, const allocator_type &allocator) BSLS_KEYWORD_NOEXCEPT | |
| function (allocator_arg_t, const allocator_type &allocator, nullptr_t) BSLS_KEYWORD_NOEXCEPT | |
| template<class FUNC > | |
| function (BSLS_COMPILERFEATURES_FORWARD_REF(FUNC) func, typename enable_if< ! IsReferenceCompatible< typename Decay< FUNC >::type, function >::value &&IsInvocableWithPrototype< typename Decay< FUNC >::type >::value &&! MovableRefUtil::IsMovableReference< FUNC >::value, int >::type=0) | |
| template<class FUNC > | |
| function (const BloombergLP::bslmf::MovableRef< FUNC > &func, typename enable_if< ! IsReferenceCompatible< typename Decay< FUNC >::type, function >::value &&IsInvocableWithPrototype< typename Decay< FUNC >::type >::value, int >::type=0) | |
| template<class FUNC > | |
| function (allocator_arg_t, const allocator_type &allocator, BSLS_COMPILERFEATURES_FORWARD_REF(FUNC) func, typename enable_if< ! IsReferenceCompatible< typename Decay< FUNC >::type, function >::value &&IsInvocableWithPrototype< typename Decay< FUNC >::type >::value, int >::type=0) | |
| function (const function &original) | |
| function (allocator_arg_t, const allocator_type &allocator, const function &original) | |
| function (BloombergLP::bslmf::MovableRef< function > original) BSLS_KEYWORD_NOEXCEPT | |
| function (allocator_arg_t, const allocator_type &allocator, BloombergLP::bslmf::MovableRef< function > original) | |
| function & | operator= (const function &rhs) |
| function & | operator= (BloombergLP::bslmf::MovableRef< function > rhs) |
| template<class FUNC > | |
| enable_if<!IsReferenceCompatible< typenameDecay< FUNC >::type, function >::value &&IsInvocableWithPrototype< typenameDecay< FUNC >::type >::value, function & >::type | operator= (BSLS_COMPILERFEATURES_FORWARD_REF(FUNC) rhs) |
| template<class FUNC > | |
| enable_if< IsInvocableWithPrototype< typenameDecay< FUNC >::type >::value, function & >::type | operator= (bsl::reference_wrapper< FUNC > rhs) BSLS_KEYWORD_NOEXCEPT |
| function & | operator= (nullptr_t) BSLS_KEYWORD_NOEXCEPT |
Set this object to empty and return *this. | |
| void | swap (function &other) BSLS_KEYWORD_NOEXCEPT |
| template<class TP > | |
| TP * | target () BSLS_KEYWORD_NOEXCEPT |
| operator UnspecifiedBool () const BSLS_KEYWORD_NOEXCEPT | |
| allocator_type | get_allocator () const BSLS_KEYWORD_NOEXCEPT |
| template<class TP > | |
| const TP * | target () const BSLS_KEYWORD_NOEXCEPT |
| const std::type_info & | target_type () const BSLS_KEYWORD_NOEXCEPT |
| operator BloombergLP::bdef_Function< PROTOTYPE * > & () BSLS_KEYWORD_NOEXCEPT | |
| operator const BloombergLP::bdef_Function< PROTOTYPE * > & () const BSLS_KEYWORD_NOEXCEPT | |
| BloombergLP::bslma::Allocator * | allocator () const BSLS_KEYWORD_NOEXCEPT |
| bool | isInplace () const BSLS_KEYWORD_NOEXCEPT |
Detailed Description
class bsl::function< PROTOTYPE >
This class template implements the C++ Standard Library std::function template, enhanced for allocator support as per Standards Proposal P0987. An instantiation of this template generalizes the notion of a pointer to a function having the specified PROTOTYPE expressed as a function type (e.g., int(const char *, float)). An object of this class wraps a copy of the callable object specified at construction (if any), such as a function pointer, member-function pointer, member-data pointer, or functor object. The wrapped object (called the target or target object) is owned by the bsl::function object (unlike the function pointer that it mimics). Invoking the bsl::function object will invoke the target (or throw an exception, if there is no target). Note that function will compile only if PROTOTYPE is a function type.
To optimize away many heap allocations, objects of this type have a buffer into which small callable objects can be stored. In order to qualify for this small-object optimization, a callable type must not only fit in the buffer but must also be nothrow move constructible. The latter constraint allows this type to be nothrow move constructible and nothrow swappable, as required by the C++ Standard. The small object buffer is guaranteed to be large enough to hold a pointer to function, pointer to member function, pointer to member data, a bsl::reference_wrapper, or an empty struct. Although the standard does not specify a minimum size beyond the aforementioned guarantee, many small structs will fit in the small object buffer, as defined in the bslstl_function_smallobjectoptimization component.
See bslstl_function
Member Typedef Documentation
◆ allocator_type
| typedef Function_Rep::allocator_type bsl::function< PROTOTYPE >::allocator_type |
Constructor & Destructor Documentation
◆ function() [1/3]
|
inline |
Create an object wrapping the specified func callable object. Use the default allocator to supply memory. If func is a null pointer or null pointer-to-member, then the resulting object will be empty. This constructor will not participate in overload resolution if func is of the same type as (or reference compatible with) this object (to avoid ambiguity with the copy and move constructors) or is an integral type (to avoid matching null pointer literals). In C++03, this function will not participate in overload resolution if FUNC is a MovableRef (see overload, below), and instantiation will fail unless FUNC is invocable using the arguments and return type specified in PROTOTYPE. In C++11 and later, this function will not participate in overload resolution if FUNC is not invocable using the arguments and return type specified in PROTOTYPE. Note that this constructor implicitly converts from any type that is so invocable.
Implementation Note
◆ function() [2/3]
|
inlineexplicit |
Create an object wrapping the specified func callable object. This constructor (ctor 2) is identical to the previous constructor (ctor 1) except that, in C++03 ctor 2 provides for explicit construction from a MovableRef referencing a callable type, rather than an implicit conversion for FUNC not being a MovableRef. In C++11, overload resolution matching an argument of type T&& to a parameter of type T (exact match) is always preferred over matching T&& to bsl::function (conversion). In C++03, however MovableRef is not a real reference type, so it sometimes creates overload ambiguities whereby matching MovableRef<T> to T (conversion) is no better than matching MovableRef<T> to bsl::function (also conversion). This ambiguity is resolved by making this constructor from MovableRef<T> explicit, while leaving other constructor from FUNC implicit. This means that move will fail in a narrow set of cases in C++03, as shown below:
As you can see from the examples above, there are simple workarounds for the problem cases, although generic code might need to be extra careful.
Implementation Note
◆ function() [3/3]
|
inline |
Create an object wrapping the specified func callable object. Use the specified allocator (i.e., the address of a bslma::Allocator object) to supply memory. If func is a null pointer or null pointer-to-member, then the resulting object will be empty. This constructor will not participate in overload resolution if func is of the same type as (or reference compatible with) this object (to avoid ambiguity with the extended copy and move constructors) or is an integral type (to avoid matching null pointer literals). In C++03, this function will not participate in overload resolution if FUNC is a MovableRef (see overload, below), and instantiation will fail unless FUNC is invocable using the arguments and return type specified in PROTOTYPE. In C++11 and later, this function will not participate in overload resolution if FUNC is not invocable using the arguments and return type specified in PROTOTYPE. Note that this constructor implicitly converts from any type that is so invocable.
Implementation Note
Member Function Documentation
◆ BSLMF_NESTED_TRAIT_DECLARATION() [1/3]
| bsl::function< PROTOTYPE >::BSLMF_NESTED_TRAIT_DECLARATION | ( | function< PROTOTYPE > | , |
| BloombergLP::bslma::UsesBslmaAllocator | |||
| ) |
◆ BSLMF_NESTED_TRAIT_DECLARATION() [2/3]
| bsl::function< PROTOTYPE >::BSLMF_NESTED_TRAIT_DECLARATION | ( | function< PROTOTYPE > | , |
| BloombergLP::bslmf::UsesAllocatorArgT | |||
| ) |
◆ BSLMF_NESTED_TRAIT_DECLARATION() [3/3]
| bsl::function< PROTOTYPE >::BSLMF_NESTED_TRAIT_DECLARATION | ( | function< PROTOTYPE > | , |
| bsl::is_nothrow_move_constructible | |||
| ) |
◆ operator UnspecifiedBool()
|
inline |
(C++03 only) Return a null value if this object is empty, otherwise an arbitrary non-null value. Note that this operator will be invoked implicitly in boolean contexts such as in the condition of an if or while statement, but does not constitute an implicit conversion to bool.
◆ operator=() [1/2]
|
inline |
Destroy the current target (if any) of this object, then set the target to the specified rhs wrapper containing a reference to a callable object and return *this. The result is equivalent to having constructed *this from rhs and this->get_allocator(). Note that this assignment is a separate overload only because it is unconditionally noexcept.
Implementation Note
◆ operator=() [2/2]
|
inline |
Set the target of this object to the specified rhs callable object, destroy the previous target (if any), and return *this. The result is equivalent to having constructed *this from std::forward<FUNC>(rhs) and this->get_allocator(). Note that this assignment operator will not participate in overload resolution if func is of the same type as this object (to avoid ambiguity with the copy and move assignment operators.) In C++03, instantiation will fail unless FUNC is invocable with the arguments and return type specified in PROTOTYPE. In C++11 and later, this assignment operator will not participate in overload resolution unless FUNC is invocable with the arguments and return type specified in PROTOTYPE.
Implementation Note
The documentation for this class was generated from the following file:
