c++ - 在带有WM_COPYDATA消息的结构中使用LPCTSTR是否安全？

Question

我有这个结构:

typedef struct tagCOPY_PACKET
{
    TCHAR szFile[_MAX_PATH];
    GUID guidSignature;

} S_COPY_PACKET;

我准备使用WM_COPYDATA发送数据，如下所示:

CString strFile = GetFileToOpenFromFileExplorerPath();

S_COPY_PACKET sCopyDataPacket;
_tcscpy_s(sCopyDataPacket.szFile, _MAX_PATH, strFile);
sCopyDataPacket.guidSignature = CopyData_Signature;
COPYDATASTRUCT cds;
cds.dwData = COPYDATA_TYPE_MSA;
cds.cbData = sizeof(sCopyDataPacket);
cds.lpData = &sCopyDataPacket;

DWORD_PTR dwResult;
if (SendMessageTimeout(hOtherInstance, WM_COPYDATA,
                NULL, (LPARAM)(LPVOID)&cds, SMTO_BLOCK, 2000, &dwResult) != 0)
{
}

在另一端:

BOOL CMeetingScheduleAssistantDlg::OnCopyData(CWnd* pWnd, COPYDATASTRUCT* pCopyDataStruct)
{
    if (pCopyDataStruct->dwData == COPYDATA_TYPE_MSA)
    {
        S_COPY_PACKET* pCopyPacket = (S_COPY_PACKET*)(pCopyDataStruct->lpData);
        if (pCopyPacket->guidSignature != CopyData_Signature)
        {
            // Bad GUID
            return FALSE;
        }

        if (GetLastActivePopup() != this) // Popup windows!
        {
            // TODO: Tell user?
            return FALSE;
        }

        theApp.SetFileToOpenFromFileExplorer(pCopyPacket->szFile);

        OpenFileFromFileExplorer();

        return TRUE;
    }

    return FALSE;
}

它工作正常。我只是想知道更改这样的结构是否可以接受:

typedef struct tagCOPY_PACKET
{
    LPCTSTR lpszFile;
    GUID guidSignature;

} S_COPY_PACKET;

然后使用:

S_COPY_PACKET sCopyDataPacket;
sCopyDataPacket.lpszFile = strFile.GetBufferSetLength(_MAX_PATH);
sCopyDataPacket.guidSignature = CopyData_Signature;
COPYDATASTRUCT cds;
cds.dwData = COPYDATA_TYPE_MSA;
cds.cbData = sizeof(sCopyDataPacket);
cds.lpData = &sCopyDataPacket;
...

并且，一旦消息已发布并处理:

strFile.ReleaseBuffer();

将LPCTSTR方法与WM_COPYDATA一起使用是否安全？如果可以，为什么？

Answer 1

documentation of WM_COPYDATA 说:

The data being passed must not contain pointers or other references to objects not accessible to the application receiving the data.

因此，当CMeetingScheduleAssistantDlg位于其他可执行文件中时，您不能传递LPCTSTR值。如果它在同一可执行文件中，则可能会起作用。