trying to run commend on cmd throw c++ using createprocces (API)? - c++

Question

bool execute()
{
STARTUPINFO si;
PROCESS_INFORMATION pi;
bool flag = true;
ZeroMemory(&si, sizeof(si));
si.cb = sizeof(si);
ZeroMemory(&pi, sizeof(pi));
string f = "dir desktop"
if (CmdLine.parameter != "")
{
LPSTR l1 = const_cast<char *>(f.c_str());
CreateProcess(NULL, l1, NULL, NULL, false, 0, NULL, NULL, &si, &pi);
flag = true;
// WaitForSingleObject(pi.hProcess, INFINITE);
// // Close process and thread handles.
// CloseHandle(pi.hProcess);
// CloseHandle(pi.hThread);
//}
}
return flag;
}
I'm trying to run cmd command by visual studio.
I'm using createprocces (API) in order to run this thing
but I can't understand why it doesn't run anything.

Answer 1

dir is a command understood by cmd.exe, it's not a program you can execute.
You can try the command cmd /k "dir desktop", properly expressed as a C++ string.
E.g.,
auto execute()
-> bool
{
STARTUPINFO si = { sizeof( si ) };
PROCESS_INFORMATION pi = {};
string f = "cmd /k \"dir desktop\"\0";
bool const ok = !!CreateProcess( 0, &f[0], 0, 0, false, 0, 0, 0, &si, &pi );
if( !ok ) { return false; }
WaitForSingleObject(pi.hProcess, INFINITE);
CloseHandle(pi.hProcess);
CloseHandle(pi.hThread);
return true;
}
Note how the calls to ZeroMemory have been replaced with C++ initialization.
Just by letting the compiler do its job you get shorter, more clear code that is more likely correct, and just as efficient (possibly more). Win win win.
Disclaimer: code not reviewed by compiler.
If the intent is to list the contents of the user's desktop folder, then note that dir desktop doesn't do that. As an interactive command in the command interpreter you could use dir %userprofile%\desktop, and that also works via the Windows Run-dialog. Depending on the command interpreter's behavior for command line arguments it may work directly via CreateProcess, or not.
Generally, when using Windows API level functions it's preferable to use the wchar_t-based text based functions, i.e. define UNICODE before including <windows.h> (or use the ...W functions explicitly).

Answer 2

If you call CreateProcess() with the first parameter set to NULL, then you have to make sure that l1 starts with the module name to call.
As dir is an internal command of the command processor and not an executable, you have to use cmd as module name and give the rest of the parameter as cmd expects them.
So try the following:
string f = "cmd /c=dir desktop";