C/C++笔记之char 与wchar_t 的相互转换

爱被打了一巴掌 2021-12-21 11:43 551阅读 0赞

char \*和wchar\_t \*的相互转换，可使用标准库函数

size\_t mbstowcs(wchar\_t \*wcstr, const char \*mbstr, size\_t count)和size\_t wcstombs(char \*mbstr, const wchar\_t \*wcstr, size\_t count)

**注意**

微软文档对mbstowcs的描述有误，[mbstowcs, \_mbstowcs\_l | Microsoft Docs][mbstowcs_ _mbstowcs_l _ Microsoft Docs]

![1277302-20190303201413484-746296773.png][]

若mbstowcs成功地转换了源字符串，它返回已转换的多字节字符的数量。这句话是错误的，应参考cppreference的描述，[std::mbstowcs - cppreference.com][std_mbstowcs - cppreference.com]

![1277302-20190302144805684-480826474.png][]

成功，则返回写入目标数组的宽字符的数量，不包括L'\\0'。这句才是正解

另外，根据微软文档的描述，若参数wcstr为NULL，函数返回目标字符串的要求大小（以宽字符为单位）

多字节字符串到宽字符串的转换示例

#include <iostream>
    using namespace std;
    int main()
    {
        setlocale(LC_ALL, "");
        const char *mbString = "多字节字符串到宽字符串的转换";
        size_t requiredSize = mbstowcs(nullptr, mbString, 0);
        wchar_t *wcString = new wchar_t[requiredSize + 1];
        if (static_cast<size_t>(-1) == mbstowcs(wcString, mbString, requiredSize + 1))
        {
            cout << "Couldn't convert string: invalid multibyte character." << endl;
        }
        else
        {
            wcout << "wcString: " << wcString << endl;
        }
        delete[] wcString;
        return 0;
    }

宽字符串到多字节字符串的转换示例

#include <iostream>
    using namespace std;
    int main()
    {
        setlocale(LC_ALL, "");
        const wchar_t *wcString = L"宽字符串到多字节字符串的转换";
        size_t requiredSize = wcstombs(nullptr, wcString, 0);
        char *mbString = new char[requiredSize + 1];
        if (static_cast<size_t>(-1) == wcstombs(mbString, wcString, requiredSize + 1))
        {
            cout << "Couldn't convert string: invalid wide character" << endl;
        }
        else
        {
            cout << mbString << endl;
        }
        delete[] mbString;
        return 0;
    }

转载于:https://www.cnblogs.com/buyishi/p/10460797.html

[mbstowcs_ _mbstowcs_l _ Microsoft Docs]: https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/mbstowcs-mbstowcs-l?f1url=https%3A%2F%2Fmsdn.microsoft.com%2Fquery%2Fdev15.query%3FappId%3DDev15IDEF1%26l%3DEN-US%26k%3Dk%28STDLIB%2Fmbstowcs%29;k%28mbstowcs%29;k%28DevLang-C%2B%2B%29;k%28TargetOS-Windows%29%26rd%3Dtrue&view=vs-2017
[1277302-20190303201413484-746296773.png]: /images/20211220/89d5e1ab12a34f888ccb8b0732440a6a.png
[std_mbstowcs - cppreference.com]: https://en.cppreference.com/w/cpp/string/multibyte/mbstowcs
[1277302-20190302144805684-480826474.png]: /images/20211220/f7a44551013b48e781886fb51d72dc89.png