std::function::operator bool

 

C++

Language

Concepts

Utilities library

Strings library

Containers library

Algorithms library

Iterators library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

 

Utilities library

Type support (basic types, RTTI, type traits)

Dynamic memory management

Error handling

Program utilities

Variadic functions

Date and time

Function objects

initializer_list (C++11)

bitset

hash (C++11)

Relational operators

rel_ops::operator!= rel_ops::operator> rel_ops::operator<= rel_ops::operator>=

Pairs and tuples

pair

tuple (C++11)

piecewise_construct_t (C++11)

piecewise_construct (C++11)

Swap, forward and move

swap

forward (C++11)

move (C++11)

move_if_noexcept (C++11)

declval (C++11)

 

Function objects

Operator wrappers
plus minus negate multiplies divides modulus logical_and logical_or logical_not	equal_to not_equal_to greater less greater_equal less_equal bit_and bit_or bit_xor
Negators
unary_negate binary_negate	not1 not2
Bind
bind (C++11)
is_bind_expression (C++11)
is_placeholder (C++11)
_1, _2, _3, ... (C++11)
Function wrappers
mem_fn (C++11)
function (C++11)
bad_function_call (C++11)
Reference wrappers
reference_wrapper (C++11)
ref cref (C++11) (C++11)
Deprecated binders and adaptors
unary_function (deprecated)
binary_function (deprecated)
ptr_fun (deprecated)
pointer_to_unary_function (deprecated)
pointer_to_binary_function (deprecated)
mem_fun (deprecated)
mem_fun_t mem_fun1_t const_mem_fun_t const_mem_fun1_t (deprecated) (deprecated) (deprecated) (deprecated)
mem_fun_ref (deprecated)
mem_fun_ref_t mem_fun1_ref_t const_mem_fun_ref_t const_mem_fun1_ref_t (deprecated) (deprecated) (deprecated) (deprecated)
binder1st binder2nd (deprecated) (deprecated)
bind1st bind2nd (deprecated) (deprecated)

 

std::function

Member functions

function::function

function::~function

function::operator=

function::swap

function::assign

function::operator bool

function::operator()

function::target_type

function::target

Non-member functions

operator== operator!=

std::swap(std::function)

Helper classes

std::uses_allocator<std::function>

 

explicit operator bool() const;		(since C++11)

Checks whether the stored callable object is valid.

Parameters

(none)

Return value

true if the stored callable object is valid, false otherwise.

Exceptions

noexcept specification:  

noexcept

  (since C++11)