为什么超负荷的unique_ptr复位（指针p =指针（））和reset（nullptr_t）？

问题描述

Accroding到，

 无效复位（PTR指针指针=（））;模板＆LT;类U＆GT;
无效复位（U）=删除;无效复位（的std :: nullptr_t P）;
 

Now that reset(nullptr) is equivalent to reset(pointer()), why does the latter exist?

If I want to reset an array form unique_ptr, why can I not just use rest(pointer())?

解决方案

The

template< class U >
void reset( U ) = delete;

would be chosen for a call with nullptr argument, if not for

void reset( std::nullptr_t p );

That's why it exists, to allow the call with nullptr.

---

Example (compile with FIX defined to suppress the compilation error):

#include <cstddef>      // std::nullptr_t

struct S
{
    void reset( char* ) {}

    template< class Type >
    void reset( Type ) = delete;

    #if FIX
    void reset( std::nullptr_t ) {}
    #endif
};

auto main() -> int
{
    S().reset( nullptr );    // Fails when FIX is not defined.
}

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