booloperator==(std::nullptr_t, conststd::function<R(ArgTypes...)>&f)noexcept; (2)(since C++11) (until C++20) template<classR,class...ArgTypes> booloperator!=(conststd::function<R(ArgTypes...)>&f, std::nullptr_t)noexcept;
std::strong_ordering operator<=>( const std::shared_ptr<T>& lhs, std::nullptr_t ) noexcept; (20) (C++20 起)比较二个 shared_ptr<T> 对象或将 shared_ptr<T> 与空指针比较。 注意shared_ptr 的比较运算符简单地比较指针值;不比较所指向的实际对象。对 shared_ptr 定义operator< 允许将 shared_...
unique_ptr&operator=(std::nullptr_t)noexcept; (3)(C++23 起为constexpr) unique_ptr&operator=(constunique_ptr&)=delete; (4) 1)移动赋值运算符。从r转移所有权到*this,如同在调用reset(r.release())后立即将std::forward<Deleter>(r.get_deleter())赋给get_deleter()。
u2.p is equal to the pre-transfer u.p, u.p is equal to nullptr, and if the pre-transfer u.d maintained state, such state has been transferred to u2.d. As in the case of a reset,u2 must properly dispose of its pre-transfer owned object via the pre-transfer associated deleter befo...
#include <iostream> // 自定义分配器 void* operator new(std::size_t size) { static int counter = 0; counter++; if (counter > 1) { return nullptr; // 第二次调用时返回空指针 } return malloc(size); } void operator delete(void* ptr) noexcept { free(ptr); } int main() { int* ...
i run the python predictor.py ,there are some errors: [11:38:15] /home/xuting/ocr/mxnet/dmlc-core/include/dmlc/./logging.h:308: [11:38:15] src/core/op.cc:55: Check failed: op != nullptr Operator WarpCTC is not registered Stack trace retu...
检查*this 是否占有对象,即是否有 get() != nullptr。 参数(无) 返回值若*this 占有对象则为 true,否则为 false。 示例运行此代码 #include <iostream> #include <memory> int main() { std::unique_ptr<int> ptr(new int(42)); if (ptr) std::cout << "重置前,ptr 为: " << *ptr << '\...
basic_ostream& operator<<( std::nullptr_t ); (10) (since C++17) basic_ostream& operator<<( short value ); (11) basic_ostream& operator<<( int value ); (12) basic_ostream& operator<<( unsigned short value ); (13) basic_ostream& operator<<( unsigned int value ); (14) ...
operator =() 重载了 = 赋值号,从而可以将 nullptr 或者一个右值 unique_ptr 指针直接赋值给当前同类型的 unique_ptr 指针。...operator 重载了 [] 运算符,当 unique_ptr 指针指向一个数组时,可以直接通过 [] 获取指定下标位置处的数据。...::shared+ptr 可以通过访问某资源的引用计数来确定是否自己是最...
..) -> std::false_type; static constexpr bool value = decltype(test<T>(nullptr))::value; }; 上述代码定义了一个模板结构体has_equal_operator,它包含了两个静态成员函数test。第一个test函数使用了SFINAE(Substitution Failure Is Not An Error)技术,通过尝试调用"=="运算符来检查operator==是否存在。