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In C, function pointers can be converted into function objects through the std::function template: Use std::function to wrap function pointers into function objects. Use the std::function::target member function to convert a function object to a function pointer. This transformation is useful in scenarios such as event handling, function callbacks, and generic algorithms, providing greater flexibility and code reusability.
In C, function pointer and function object are two closely related concepts that allow us Work with functions in a more flexible way. In some cases, you may want to convert a function pointer to a function object, or vice versa.
You can convert function pointer to function object by using std::function
template. std::function
Accepts any callable entity (including function pointers) and wraps it in a callable object.
// 函数指针 int add(int a, int b) { return a + b; } // 转换为函数对象 std::function<int(int, int)> add_fn = add; // 调用函数对象 int result = add_fn(10, 20); // 结果为 30
To convert function object to function pointer, you can use the std::function::target
member function. This function returns a function pointer to the underlying function of the function object.
std::function<int(int, int)> add_fn = [](int a, int b) { return a + b; }; // 转换为函数指针 int (*add_ptr)(int, int) = add_fn.target<int (*)(int, int)>(); // 调用函数指针 int result = add_ptr(10, 20); // 结果为 30
In the following scenarios, you may find it useful to convert a function pointer to a function object or vice versa:
std::function
Can be used to pass any callable entity to a generic algorithm, providing flexibility. By understanding the conversion between function pointers and function objects, you can write more flexible and reusable code.
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