你能把一个LPTSTR转换为BSTR吗？ [英] Can you cast a LPTSTR to a BSTR?

问题描述

将LPTSTR直接投放到BSTR是合法的吗？

根据我的了解BSTR ，直接将一个LPTSTR转换为BSTR会留下一个损坏的长度前缀。示例代码显式声明，字符串文字不能存储到BSTR。任何人都可以确认一个LPTSTR / LPCTSTR不能直接转换到BSTR而不破坏长度前缀？

编辑：

我的困惑是看到这在调用COM对象时使用。事实证明，当编译COM dll时，生成一个.tli文件，创建一个中间方法。此方法接受类型 _bstr_t 。 _bstr_t 可以在其构造函数中使用 LPTSTR ，所以一切顺利。

LPTSTR 因此是 LPWSTR ，则可以使用 SysAllocString 将指针转换为宽字符串转换为 BSTR 。

无法直接投放，因为两者有不同的内存表示。

如果使用C ++，您可以使用 _bstr_t 类，以简化 BSTR 字符串的使用。

Is it legal to cast a LPTSTR directly to a BSTR?

Based on my understanding of BSTR, casting a LPTSTR to a BSTR directly will leave you with a corrupted length prefix. The example code explicitly states that a string literal cannot be stored to a BSTR. Can anyone confirm for me that a LPTSTR/LPCTSTR cannot be cast directly to a BSTR without corrupting the length prefix?

EDIT:

My confusion is from seeing this used in a call to a COM object. It turns out that when compiling the COM dll, a .tli file is generated that creates an intermediate method. This method takes type _bstr_t. The _bstr_t can take LPTSTR in its constructor, so everything works smoothly.

解决方案

If your program is unicode and your LPTSTR therefore is a LPWSTR, you can use SysAllocString to convert from a pointer to a wide character string to BSTR.

A direct cast is not possible because the two have different memory representations.

If you use C++, you can use the _bstr_t class to simplify the usage of BSTR strings.

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