将std :: wstring转换为WCHAR * [英] Convert std::wstring to WCHAR*

问题描述

我不知道如何将 std :: wstring 转换为 WCHAR *

I have no idea how to convert a std::wstring to a WCHAR*

std::wstring wstrProcToSearch;
WCHAR * wpProcToSearch = NULL;

std::wcin >> wstrProcToSearch;  // input std::wstring
// now i need to convert the wstring to a WCHAR*

有人知道如何实现吗？

推荐答案

如果要从 std转换： ：wstring 到 const WCHAR * （即返回的指针为字符串内容提供只读访问），然后调用 std :: wstring :: c_str（）方法就可以了：

If you want to convert from std::wstring to const WCHAR* (i.e. the returned pointer gives read-only access to the string content), then calling std::wstring::c_str() method is just fine:

std::wstring wstrProcToSearch;
std::wcin >> wstrProcToSearch;  // input std::wstring

// Convert to const WCHAR* (read-only access)
const WCHAR * wpszProcToSearch = wstrProcToSearch.c_str();

相反，如果要修改 std :: wstring 的内容不同。您可以使用& wstr [0] （其中 wstr 是 std :: wstring ）以访问 std :: wstring 的内容（从其第一个字符的地址开始，并注意该字符连续存储在内存中），但您必须注意不要溢出字符串的预分配内存。

Instead, if you want to modify std::wstring's content, things are different. You can use &wstr[0] (where wstr is a non-empty instance of std::wstring) to access the content of the std::wstring (starting from the address of its first characters, and noting that characters are stored contiguously in memory), but you must pay attention to not overrun string's pre-allocated memory.

通常，如果您有 std :: wstring 长度为 L ，则可以访问索引 0 $ b $中的字符b到（L-1）。

覆盖终止的'\0' （位于索引 L ）是未定义的行为（实际上，在Visual C ++上是可以的，至少在VC9 / VS2008和VC10 / VS2010中是可以的）。

In general, if you have a std::wstring of length L, you can access characters from index 0 to (L-1).
Overwriting the terminating '\0' (located at index L) is undefined behavior (in practice, it's OK on Visual C++, at least with VC9/VS2008 and VC10/VS2010).

如果字符串的大小不合适（即，它的大小不足以满足您的需要），则可以调用 std :: wstring :: resize（）到m为新角色留出空间（即调整内部 std :: wstring 的缓冲区的大小），然后使用& wstr [0] 进行读写 std :: wstring 的内容。

If the string has not the proper size (i.e. it's not big enough for your needs), then you can call std::wstring::resize() to make room for new characters (i.e. resizing internal std::wstring's buffer), and then use &wstr[0] to read-write std::wstring's content.

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