placement new 问题
#include <new>class CTest{public: CTest() {} CTest( int) {} /* 代码*/}; char strBuff[ sizeof( CTest) * 10 + 100]; CTest * pBuffer = ( CTest *)strBuff; // 缺省构造 CTest * pFirst = new(pBuffer) CTest; // 缺省构造 CTest * pSecond = new(pBuffer + 1) CTest; // 带参数的构造; // 不理会返回的指针 new(pBuffer + 2) CTest( 5); // 带参数的构造 CTest * pFourth = new( pBuffer + 3) CTest( 10); // 缺省构造 CTest * pFifth = new(pBuffer + 4) CTest(); // 构造多个元素(缺省构造) CTest * pMultipleElements = new(pBuffer + 5) CTest[ 5];
class CTest{public: CTest() {} CTest( int) {}};int main(int argc, char* argv[]){ char strBuff[ sizeof( CTest) * 10 + 100]; CTest * pBuffer = ( CTest *)strBuff; // 缺省构造 CTest * pFirst = new(pBuffer) CTest; // 缺省构造 CTest * pSecond = new(pBuffer + 1) CTest; // 带参数的构造; // 不理会返回的指针 new(pBuffer + 2) CTest( 5); // 带参数的构造 CTest * pFourth = new( pBuffer + 3) CTest( 10); // 缺省构造 CTest * pFifth = new(pBuffer + 4) CTest(); // 构造多个元素(缺省构造) CTest * pMultipleElements = new(pBuffer + 5) CTest[ 5]; system("pause"); return 0;}
[解决办法]
CTest似乎没有存储空间吧,具体怎样不太了解,但感觉上sizeof(CTest)=0
另外,你可以这样试试:int pBuffer;CTest *pTest=(CTest*)strBuf;pBuffer = (int)pTest; CTest * pFirst = new(pBuffer) CTest;
……
[解决办法]
测试了一下,将代码