std::is_pointer 定义于头文件<type_traits> template<classT> structis_pointer; (C++11 起) 检查T是否为指向对象指针或指向函数指针(但不是指向成员/成员函数指针)。若T是对象/函数指针类型,则提供等于true的成员常量value。否则,value等于false。 添加is_pointer或is_pointer_v(C++17 起)的特化的程序行为未...
std::bit_and std::bit_or std::bit_xor std::bit_not std::boyer_moore_horspool_searcher std::unary_function std::binary_function std::ptr_fun std::pointer_to_unary_function std::pointer_to_binary_function std::mem_fun_t, std::mem_fun1_t, std::const_mem_fun_t, std::const_mem_...
operators (std::unique_ptr) operators (std::variant) Program support utilities setjmp SIGABRT SIGFPE SIGILL SIGINT SIGSEGV SIGTERM SIG_DFL SIG_ERR SIG_IGN std::abort std::addressof std::add_const std::add_cv std::add_lvalue_reference std::add_pointer std::add_rvalue_reference std::add_...
std::pointer_to_unary_function From cppreference.com <cpp |utility |functional Function objects template< classArg, classResult >classpointer_to_unary_function:publicstd::unary_function<Arg, Result>; (deprecated in C++11) (removed in C++17) ...
pointer_safety::relaxed All pointers are considered valid and may be dereferenced or deallocated. See also get_pointer_safety (C++11)(removed in C++23) returns the current pointer safety model (function) Retrieved from "https://en.cppreference.com/mwiki/index.php?title=cpp/memory/gc/poi...
bar = std::static_pointer_cast<B>(foo); std::cout << "foo's static type: " << foo->static_type << '\n'; std::cout << "foo's dynamic type: " << foo->dynamic_type << '\n'; std::cout << "bar's static type: " << bar->static_type << '\n'; std::cout << "...
std::is_pointer 是一元类型特征 (UnaryTypeTrait) 。 检查T 是否为指向对象或函数的指针(包括 void 的指针,但不包括成员指针),或其 cv 限定版本。如果 T 是对象/函数指针类型,那么提供的成员常量 value 等于true。否则,value 等于false。 如果程序添加了 std::is_pointer 或std::is_pointer_v 的特化,...
std::is_pointer是false为std::nullptr_t因为它不是内置的指针类型。 例 二次 代码语言:javascript 复制 #include <iostream> #include <type_traits> int main() { std::cout << std::boolalpha << std::is_null_pointer< decltype(nullptr) >::value << ' ' << std::is_null_pointer< int* >:...
std::shared_ptr其存储的指针是从r%27s使用强制转换表达式存储指针。如果r是空的,新的也是空的shared_ptr%28但其存储的指针不一定为空%29。 否则,新的shared_ptr将与r,但如果dynamic_cast由dynamic_pointer_cast返回空指针。 让Y成typenamestd::shared_ptr<T>::element_type,然后产生的std::shared_ptr%27s...
#include <type_traits>intmain(){structA{intm;voidf(){}};intA::*mem_data_ptr=&A::m;// a pointer to member datavoid(A::*mem_fun_ptr)()=&A::f;// a pointer to member functionstatic_assert(!std::is_pointer<A>::value&&!std::is_pointer_v<A>// same thing as above, but in...