How to execute a simple command line with CreateProcess?

Question

I'd like to execute a simple command line but without to make a window appear. Therefore I can't use System and have to use CreateProcess as far as I know. So I have the following code for example:

//.../

CreateProcess(NULL,input,NULL,NULL,false,NORMAL_PRIORITY_CLASS | 
 CREATE_NO_WINDOW,NULL,NULL,&startInf,&procInf);//)

//.../

If input is a line like "ping www.google.com -n 2" it seems to work. What I need is the deletion-function though. Therefore I tried a lot of variations like:

input = "rd /S /Q \"D:\\ALEX_DATEN\\PC\\C++\\bla\"";

and

  input = "rd /S /Q \"D:/DATEN/PC/C++/bla\"";

But nothing happens and the function returns failure :/ If I write it as a .bat file (without using the "\" escaping chars) the deleting works perfectly!

Does anyone know what I'm doing wrong?

P.s. no, I'm not writing a destructive virus.. if that would have been my target, I would have definitely have found simpler ways...

Uhm, I don't really see why to use that. As far as I udnerstand here: msdn.microsoft.com/en-us/library/windows/desktop/… it wants to execute a file but I just need to execute a string... — DragonGamer
cppguy is right, imo; ShellExecute is designed for running command lines, whereas CreateProcess is designed for running a specific executable file. So, as I see it, some of your options are 1) Use ShellExecute, 2) Create a dummy executable that wraps ShellExecute (or something like that) and run the dummy via CreateProcess, or 3) see if you can directly execute the binary that implements the rd command. IMO, ShellExecute is the path of least resistance. — WeirdlyCheezy
rd is a command built into the shell, so you can't execute it (at least directly) with CreateProcess. To do it, you'd need to execute cmd.exe as the executable, and have it execute your rd /S .... — Jerry Coffin
Oh okey o-o Interesting. So does that means that I can place as the argument lpFile, simply the command line? — DragonGamer

BigBoss BigBoss · Accepted Answer · 2012-10-16T19:26:52

Some system command like rd, del and ... are not actual executable Images (e.g. .exe Files), so you can't execute/run them using CreateProcess they are built-in commands that known to cmd(command interpreter of windows) so you should create cmd and pass your command to it:

wchar_t cmd[ MAX_PATH ];
size_t nSize = _countof(cmd);
_wgetenv_s( &nSize, cmd, L"COMSPEC" );
BOOL b = CreateProcessW( cmd, input, NULL, NULL, FALSE,
    NORMAL_PRIORITY_CLASS | CREATE_NO_WINDOW, NULL, NULL, &startInf, &procInf );

Note: Please see arguments of cmd, you have to use /C to pass your command. So your command is as follow:

wchar_t input[] = L"some command";
wchar_t cmd[MAX_PATH] ;
// initialize cmd
wchar_t cmdline[ MAX_PATH + 50 ];
swprintf_s( cmdline, L"%s /c %s", cmd, input );
STARTUPINFOW startInf;
memset( &startInf, 0, sizeof startInf );
startInf.cb = sizeof(startInf);
// If you want to redirect result of command, set startInf.hStdOutput to a file
// or pipe handle that you can read it, otherwise we are done!
PROCESS_INFORMATION procInf;
memset( &procInf, 0, sizeof procInf );
BOOL b = CreateProcessW( NULL, cmdline, NULL, NULL, FALSE,
    NORMAL_PRIORITY_CLASS | CREATE_NO_WINDOW, NULL, NULL, &startInf, &procInf );
DWORD dwErr = 0;
if( b ) {
    // Wait till cmd do its job
    WaitForSingleObject( procInf.hProcess, INFINITE );
    // Check whether our command succeeded?
    GetExitCodeProcess( procInfo.hProcess, &dwErr );
    // Avoid memory leak by closing process handle
    CloseHandle( procInfo.hProcess );
} else {
    dwErr = GetLastError();
}
if( dwErr ) {
    // deal with error here
}

How to execute a simple command line with CreateProcess?

2 Answers