调用CreateProcessAsUser时，是否需要将exe路径指定为lpCommandLine中的第一个参数？

Question

I can't seem to find a definitive answer to this. My goal is to start a process using a user token. Say, the process in question is started as such:

"C:\My folder\My proc.exe" param=1

So when I specify lpCommandLine parameter for the CreateProcessAsUser API, do I need to specify executable path as the 1st parameter as such:

LPCTSTR pStrExePath = L"C:\\My folder\\My proc.exe";

TCHAR buffCmdLine[MAX_PATH];
if(SUCCEEDED(::StringCchPrintf(buffCmdLine, MAX_PATH, 
    L"\"%s\" %s", pStrExePath, L"param=1")))

bResult = CreateProcessAsUser(
    hToken,            // client's access token
    pStrExePath,       // file to execute
    buffCmdLine,       // command line
    NULL,              // pointer to process SECURITY_ATTRIBUTES
    NULL,              // pointer to thread SECURITY_ATTRIBUTES
    FALSE,             // handles are not inheritable
    NORMAL_PRIORITY_CLASS | CREATE_NEW_CONSOLE | CREATE_UNICODE_ENVIRONMENT,   // creation flags
    envBlock,          // pointer to new environment block 
    NULL,              // name of current directory 
    &si,               // pointer to STARTUPINFO structure
    &pi                // receives information about new process
);

Or can I omit the exe path and do this?

LPCTSTR pStrExePath = L"C:\\My folder\\My proc.exe";

TCHAR buffCmdLine[MAX_PATH];
if(SUCCEEDED(::StringCchCopy(buffCmdLine, MAX_PATH, L"param=1")))

bResult = CreateProcessAsUser(
    hToken,            // client's access token
    pStrExePath,       // file to execute
    buffCmdLine,       // command line
    NULL,              // pointer to process SECURITY_ATTRIBUTES
    NULL,              // pointer to thread SECURITY_ATTRIBUTES
    FALSE,             // handles are not inheritable
    NORMAL_PRIORITY_CLASS | CREATE_NEW_CONSOLE | CREATE_UNICODE_ENVIRONMENT,   // creation flags
    envBlock,          // pointer to new environment block 
    NULL,              // name of current directory 
    &si,               // pointer to STARTUPINFO structure
    &pi                // receives information about new process
);

They both seem to work.

Answer 1

Reading the documentation, both cases should work.

From MSDN

If both lpApplicationName and lpCommandLine are non-NULL, *lpApplicationName specifies the module to execute, and *lpCommandLine specifies the command line . The new process can use GetCommandLine to retrieve the entire command line . Console processes written in C can use the argc and argv arguments to parse the command line. Because argv[0] is the module name, C programmers generally repeat the module name as the first token in the command line .

I agree that the documentation may be clearer saying that it accepts the argument part of the command line or the full command line in lpCommandLine when lpApplicationName is non-NULL.

UPDATE : The documentation is better in the case lpApplicationName is NULL

If lpApplicationName is NULL, the first white space–delimited token of the command line specifies the module name...

UPDATE 2 : There is a nice documentation about these arguments Understanding CreateProcess and Command-line Arguments . Reading this documentation, I understand that there is a difference between your two cases. When you provide lpApplicationName and arguments in lpCommandLine the child process will parse the command line as it is in lpCommandLine . So if you do not duplicate the exe path, argv[0] will not represent the exe path as usual but param=1.