ShellExecuteEx不传递long命令

Question

当我将ShellExecuteEx与这样的命令"-unused parameter -action capturescreenshot -filename C:\\ATDK\\Screenshots\\abcd.jbg"一起使用时，一切都很好，Executor.exe以char* argv[]开始，拥有所有的权限。9个参数。但是，当命令有更多的符号，例如文件名为"abc...xyz.jpg“时，该进程就有argc == 1，并且命令是空的。所以在将命令发送到ShellExecute之前，在我将其更改为ShellExecute (而不是Ex )之前，这个命令是可以的，它是有效的！命令可以很长，并且已经成功地传递了。谁能解释一下有什么区别吗？下面是我填充的SHELLEXECUTEINFO代码。

std::wstringstream wss;
wss << L"-unused" << " "    // added because we need to pass some info as 0 parameter
    << L"parameter" << " "  // added because EU parser sucks
    << L"-action" << " "
    << L"capturescreenshot" << " "
    << L"-filename" << " "
    << L"C:\\ATDK\\Screenshots\\abc.jpg";

SHELLEXECUTEINFO shell_info;
ZeroMemory(&shell_info, sizeof(shell_info));

shell_info.cbSize = sizeof(SHELLEXECUTEINFO);
shell_info.fMask = SEE_MASK_ASYNCOK | SEE_MASK_NO_CONSOLE;
shell_info.hwnd = NULL;
shell_info.lpVerb = NULL;
shell_info.lpFile = L"C:/ATDK/Executor";
shell_info.lpParameters = (LPCWSTR)wss.str().c_str();
shell_info.lpDirectory = NULL;
shell_info.nShow = SW_MINIMIZE;
shell_info.hInstApp = NULL;
// 1
ShellExecuteEx(&shell_info); 
// this sucks, 
// GetLastError returns err code 2147483658, 
//FormatMessage returns The data necessary to complete this operation is not yet available

// 2 
ShellExecute(NULL, NULL, L"C:/ATDK/Executor", (LPCWSTR)wss.str().c_str(), NULL, NULL);
// OK!

Answer 1

你的窃听器在这里：

shell_info.lpParameters = (LPCWSTR)wss.str().c_str();

wss.str()返回一个临时对象，该对象在创建该对象的完整表达式结束后不再存在。在这一点之后使用它是未定义的行为。

要解决这个问题，您必须构造一个std::wstring对象，该对象的生存期足够长，以便调用ShellExecuteEx返回。

std::wstringstream wss;
wss << L"-unused" << " "
    << L"parameter" << " "
    // ...

SHELLEXECUTEINFO shell_info;
ZeroMemory(&shell_info, sizeof(shell_info));

// Construct string object from string stream
std::wstring params{ wss.str() };

shell_info.cbSize = sizeof(SHELLEXECUTEINFO);
shell_info.fMask = SEE_MASK_ASYNCOK | SEE_MASK_NO_CONSOLE;
shell_info.hwnd = NULL;
shell_info.lpVerb = NULL;
shell_info.lpFile = L"C:\\ATDK\\Executor";  // Path separator on Windows is \
shell_info.lpParameters = params.c_str();  // Use string object that survives the call
shell_info.lpDirectory = NULL;
shell_info.nShow = SW_MINIMIZE;
shell_info.hInstApp = NULL;

ShellExecuteEx(&shell_info); 

注意你的第二个电话

ShellExecute(NULL, NULL, L"C:\\ATDK\\Executor", wss.str().c_str(), NULL, NULL);

可靠的工作。即使wss.str()仍然返回一个临时表达式，它在完整表达式结束之前仍然有效(即在整个函数调用过程中)。