同样单字符和宽字符转换的的C++代码，VC下正常，QT下异常

Question

话不多说，上QT源码：

#include <QCoreApplication>
#include <QDebug>
#include <iostream>
using namespace std;

std::string ws2s(const std::wstring &ws)
{
    size_t i;
    std::string curLocale = setlocale(LC_ALL, NULL);
    setlocale(LC_ALL, "");
    const wchar_t* _source = ws.c_str();
    size_t _dsize = 2 * ws.size() + 1;
    char* _dest = new char[_dsize];
    memset(_dest, 0x0, _dsize);
    wcstombs_s(&i, _dest, _dsize, _source, _dsize);
    std::string result = _dest;
    delete[] _dest;
    setlocale(LC_ALL, curLocale.c_str());
    return result;
}

std::wstring s2ws(const std::string &s)
{
    size_t i;
    std::string curLocale = setlocale(LC_ALL, NULL);
    setlocale(LC_ALL, "chs");
    const char* _source = s.c_str();
    size_t _dsize = s.size() + 1;
    wchar_t* _dest = new wchar_t[_dsize];
    wmemset(_dest, 0x0, _dsize);
    mbstowcs_s(&i, _dest, _dsize, _source, _dsize);
    std::wstring result = _dest;
    delete[] _dest;
    setlocale(LC_ALL, curLocale.c_str());
    return result;
}


int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    std::string strTest = "1234中文abcd";
    std::wstring destWStr = s2ws(strTest);
    return a.exec();
}

QT执行效果（看右侧的内存监视）

上VC源码：

#include <afx.h>
#include <string>
#include <iostream>
using namespace std;

#pragma warning (disable: 4996)

std::string ws2s(const std::wstring &ws)
{
	size_t i;
	std::string curLocale = setlocale(LC_ALL, NULL);
	setlocale(LC_ALL, "");
	const wchar_t* _source = ws.c_str();
	size_t _dsize = 2 * ws.size() + 1;
	char* _dest = new char[_dsize];
	memset(_dest, 0x0, _dsize);
	wcstombs_s(&i, _dest, _dsize, _source, _dsize);
	std::string result = _dest;
	delete[] _dest;
	setlocale(LC_ALL, curLocale.c_str());
	return result;
}

std::wstring s2ws(const std::string &s)
{
	size_t i;
	std::string curLocale = setlocale(LC_ALL, NULL);
	setlocale(LC_ALL, "");
	const char* _source = s.c_str();
	size_t _dsize = s.size() + 1;
	wchar_t* _dest = new wchar_t[_dsize];
	wmemset(_dest, 0x0, _dsize);
	mbstowcs_s(&i, _dest, _dsize, _source, _dsize);
	std::wstring result = _dest;
	delete[] _dest;
	setlocale(LC_ALL, curLocale.c_str());
	return result;
}

int main()
{
	std::string strTest = "1234中文abcd";
	std::wstring destWStr = s2ws(strTest);
	return 0;
}

VC执行效果：

Answer 1

QT和VS采用的是不同的文本编译器， 所以源码生成时使用的 编码方式也不一样，软件跑起来自然也会不一样