Createprocess Doesn't Pass Command Line Arguments

CreateProcess command line arguments

Use std::wstring and string concatenations to build up your command line dynamically, eg:

std::wstring cmdArgslistSetChannel = L"os-util.exe";
cmdArgslistSetChannel += L" 0x273e:0x0007:0x0100";
cmdArgslistSetChannel += L" --set-channel";
cmdArgslistSetChannel += L" 11";
bSuccess = CreateProcessW(
                L"os-util.exe",
                &cmdArgslistSetChannel[0],
                NULL, NULL, TRUE, 0,  
                NULL, szFileName, &si, &pi);

Alternatively, use std::wostringstream for the buildup, and then retrieve a std::wstring from it:

std::wostringstream cmdArgslistSetChannel;
cmdArgslistSetChannel << L"os-util.exe";
cmdArgslistSetChannel << L" " << L"0x273e:0x0007:0x0100";
cmdArgslistSetChannel << L" " << L"--set-channel";
cmdArgslistSetChannel << L" " << L"11";

std::wstring cmd = cmdArgslistSetChannel.str();
bSuccess = CreateProcessW(
                L"os-util.exe",
                &cmd[0],
                NULL, NULL, TRUE, 0,  
                NULL, szFileName, &si, &pi);

Either way, you can then replace any individual substring as needed.

CreateProcess won't start the proccess with arguments

The second parameter to CreateProcess is the full command line, not just the parameters to the EXE. Lets take two examples :

CreateProcess ("c:\\notepad.exe",
               "c:\\notepad.exe c:\\wibble.txt",
               ...);

will work fine (if there is a copy of notepad.exe and a file called wibble.txt in the root of C:), whereas

CreateProcess ("c:\\notepad.exe",
               "c:\\wibble.txt",
               ...);

will launch the EXE but fail to open the file. What this means is that when the help systems calls the second parameter the command line, it ain't lying - it wants the whole command line.

Note that you can use NULL as the first parameter if the whole command line is in the second param. That's how I normally use it in fact.

C++ Winapi CreateProcess issue with command line

When both lpApplicationName and lpCommandLine are used, you need to include the executable path as the first parameter of your lpCommandLine value, even though you are specifying the executable path in the lpApplication value. The lpCommandLine is passed as-is to the spawned process, and most RTLs (especially C-based RTLs, but others as well) expect the first command-line parameter to be the executable path since that is how command-line consoles operate. This is even mentioned in the CreateProcess() documentation:

If both lpApplicationName and lpCommandLine are non-NULL, the null-terminated string pointed to by lpApplicationName specifies the module to execute, and the null-terminated string pointed to by 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.

This is also covered in MSDN Support:

INFO: Understanding CreateProcess and Command-line Arguments

Behavior of CreateProcess() When Creating a 32-bit Process

Case 1:

If the ApplicationName parameter is passed and the CommandLine parameter is NULL, then the ApplicationName parameter is also used as the CommandLine. This does not mean that you can pass additional command-line parameters in ApplicationName string. For example, the following call will fail with a "File Not Found" error:

CreateProcess( "c:\\MyApp.exe Param1 Param2", NULL, ... )

Case 2:

On the other hand, if the CommandLine parameter is non-NULL and the ApplicationName parameter is NULL, then the API attempts to extract the application name from the CommandLine parameter.

Case 3:

The flexibility of the CreateProcess() function (and a possible point of confusion) arises when you pass a valid string pointer to both the ApplicationName and CommandLine parameters. This allows you to specify the application to be executed as well as the complete command line that is passed to the application. One might assume that the command line passed to the created application is a composite of the ApplicationName and CommandLine parameters, but this is not the case. As a result, a process created by CreateProcess can receive a value other than its .exe name as its "argv[0]" parameter. The following is an example of a call to CreateProcess that produces this "abnormal" behavior:

CreateProcess( "c:\\MyApp.exe", "Param1 Param2 Param3", ...)

MyApp's arguments will be as follow:

argv[0] == "Param1"
argv[1] == "Param2"
argv[2] == "Param3"

NOTE: ANSI specifications require that argv[0] should be equal to the application name, but CreateProcess gives the calling application the flexibility to override this rule for 32-bit processes.

Case #3 applies to your situation.

Use something like this instead:

std::string Command = "<exe path>";
std::string CommandLine = "\"" + Command + "\" <parameters>";

// std::string::c_str() returns a const pointer. The first parameter
// of CreateProcessA() is const, but the second parameter must be a
// non-const pointer to writable memory, because CreateProcessW() can
// modify the data...
//
resultCreate = CreateProcessA(Command.c_str(), &CommandLine[0], ...);

std::wstring Command = L"<exe path>";
std::wstring CommandLine = L"\"" + Command + L"\" <parameters>";

// std::wstring::c_str() returns a const pointer. The first parameter
// of CreateProcessW() is const, but the second parameter must be a
// non-const pointer to writable memory, because CreateProcessW() can
// modify the data...
//
resultCreate = CreateProcessW(Command.c_str(), &CommandLine[0], ...);

Alternatively, omit lpApplicationName and specify the complete command line to lpCommandLine only:

std::string CommandLine = "\"<exe path>\" <parameters>";
resultCreate = CreateProcessA(NULL, &CommandLine[0], ...);

std::wstring CommandLine = L"\"<exe path>\" <parameters>";
resultCreate = CreateProcessW(NULL, &CommandLine[0], ...);

CreateProcess and command line arguments

You cannot use command-line redirection operators with CreateProcess() directly. You have to spawn an instance of cmd.exe and pass the operators to it instead, eg:

CreateProcess( "C:\\windows\\system32\\cmd.exe", t_str2, ...))

Where t_str2 is "/C C:\\Temp\\sift.exe < C:\\img1.pgm > C:\\img1.key". The actual path to cmd.exe can be determined by reading the %COMSPEC% environment variable.

CreateProcessW not honoring commandline

You must to supply the executable in the command

• Appname should contain the full path to the executable
• Command should contain also the argv[0]

if you want to open file t.txt with notepad than you can give as follows:

• Appname = "c:/windows/notepad.exe";
• command = "notepad c:/temp/t.txt";

You doesn't even must to supply the real program name, even fake name will do the job, since it is only a place holder.

like this: command = "fake c:/temp/t.txt";

now in notepad.exe:

• argv[0] = "notepad";
• argv[1] = "c:/temp/t.txt";

See this full example:

#include <Windows.h>
#include <iostream>

using namespace std;

int main(){
    STARTUPINFO si = {sizeof(STARTUPINFO), 0};
    si.cb = sizeof(si);
    PROCESS_INFORMATION pi = {0};
    LPTSTR AppName=L"C:/Windows/notepad.exe";
    wchar_t Command[] = L"notepad C:/Temp/t.txt"; 
    DWORD res = CreateProcess(AppName, Command, 0, 0, 0, CREATE_DEFAULT_ERROR_MODE, 0, 0, &si, &pi);
    if (res) {
        CloseHandle(pi.hThread);
        CloseHandle(pi.hProcess);
        return 0;
    } else {
        cerr<<"error..."<<GetLastError()<<endl;
    }; 
    return 0;
}

CreateProcess doesn't pass command line argument to new process's main function

It seems the OP didn't quite get why the problem occurred. The reason is a misuse of the _T macro.

Instead of this:

_tprintf( _T ("%d + %d = %d\n", val1, val2, val1+val2));

It should be this:

_tprintf( _T("%d + %d = %d\n"), val1, val2, val1+val2);

The same error appears in all of the other lines in _tmain that use _T. The _T macro takes one argument, and that is a string-literal.

Unable to pass command line to new exe created by CreateProcess

So what you need to do is write to the stdin of that process. I am not familiar with the windows CreateProcess api, so you're gonna have to do some looking yourself. This example on shows several examples with reading a file and stuff into stdin of the called process. There is no easy way to do this kind of thing, so prepare to learn lots about pipes!

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