请帮助我解决问题 [英] pls help me to fix the issue
问题描述
我正在vc ++中的UNICODE环境下执行代码.
我正在尝试读取注册表值
DWORD aType = 0;
DWORD aSize = 0;
LPTSTR aBuffer = NULL;
RegQueryValueEx(hTestKey，L"DisplayName"，NULL，& aType，NULL，& aSize);
aBuffer =(char *)malloc(sizeof(char)* aSize);
我收到以下错误..
Hi,
i am doing code under UNICODE environment in vc++.
i am trying to read the registry values
DWORD aType = 0;
DWORD aSize = 0;
LPTSTR aBuffer = NULL;
RegQueryValueEx(hTestKey, L"DisplayName" , NULL, &aType, NULL, &aSize);
aBuffer = (char *)malloc(sizeof(char)*aSize);
I got the following error..
error C2440: '=' : cannot convert from 'char *' to 'unsigned short *'
Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
how to solve it.
推荐答案
LPTSTR aBuffer = NULL;
//...
aBuffer =(char *)malloc(sizeof(char)* aSize);
LPTSTR aBuffer = NULL;
//...
aBuffer = (char *)malloc(sizeof(char)*aSize);
您应该一致地使用类型 :即LPTSTR是指向TCHAR的指针，因此:
You should use types consistently: namely a LPTSTR is a pointer to TCHAR, hence:
LPTSTR aBuffer = NULL;
//...
aBuffer = (TCHAR *) malloc(sizeof(TCHAR) * aSize);
[更新]
正如 nv3 正确指出的那样，您需要精确地aSize bytes 的缓冲区才能调用RegQueryValueEx，因此正确的分配是:
[update]
As correctly noted by nv3, you need a buffer of exactly aSize bytes in order to call RegQueryValueEx, hence the correct allocation is:
aBuffer = (TCHAR *) malloc(aSize);
[/update]
[/update]
辅助缓冲区应为字节数组.这就是您应该提供的.您将LPTSTR定义为Buffer时，会将Unicode构建转换为wchar_t *，而char *无法转换为wchar_t *.因此，请按照以下方式进行操作:
The auxiliary buffer is expected to be an array of bytes. So that is what you should provide. Your definition of a Buffer as LPTSTR translates in a Unicode build to a wchar_t* and your char* cannot be cast into that. So do it this way:
BYTE* aBuffer = NULL;
...
aBuffer = (BYTE*) malloc (aSize);
//LPTSTR aBuffer = NULL;
将aBuffer声明为char *将解决此问题.
尝试char * aBuffer = NULL;
//LPTSTR aBuffer = NULL;
Declaring the aBuffer as a char* will solve the issue.
Try char* aBuffer = NULL;
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