为什么不使用CreateProcess执行命令

Question

i hev problem with CreatProcess function introduced in windows.h header for c++. whenever i try to pass it a TCHAR variable containing a cmd command it returns error : CreateProcess failed (2) . and for this am waiting for your explanations and solutions.

consider code below:

#include <windows.h>
#include <stdio.h>
#include <tchar.h>

int _tmain( int argc, TCHAR *argv[] )
{
STARTUPINFO si;
PROCESS_INFORMATION pi;

ZeroMemory( &si, sizeof(si) );
si.cb = sizeof(si);
ZeroMemory( &pi, sizeof(pi) );

if( argc != 2 )
{
    printf("Usage: %s [cmdline]\n", argv[0]);
    return 0;
}

// Start the child process.
if( !CreateProcess( NULL,   // No module name (use command line)
    argv[1],        // Command line
    NULL,           // Process handle not inheritable
    NULL,           // Thread handle not inheritable
    FALSE,          // Set handle inheritance to FALSE
    0,              // No creation flags
    NULL,           // Use parent's environment block
    NULL,           // Use parent's starting directory
    &si,            // Pointer to STARTUPINFO structure
    &pi )           // Pointer to PROCESS_INFORMATION structure
)
{
    printf( "CreateProcess failed (%d).\n", GetLastError() );
    return 0;
}

// Wait until child process exits.
WaitForSingleObject( pi.hProcess, INFINITE );

// Close process and thread handles.
CloseHandle( pi.hProcess );
CloseHandle( pi.hThread );

}

notice:when i launch an application with specifying its path ..it works fine like=> "c:\\code.exe";

Answer 1

If you want to run a command DOS , you have to run the shell cmd before.

CreateProcess doesn't do that for you.

The option /c of cmd permits to run a command in the shell and terminate. You just have to build a command line of the type cmd /c <your command here> .

I compiled your code on VS2012 and I tried : test.exe "cmd /c dir" and it works like a charm.

From the Microsoft documentation :

To run a batch file (or a batch command), you must start the command interpreter; set lpApplicationName to cmd.exe and set lpCommandLine to the following arguments: /c plus the name of the batch file.

Source : http://msdn.microsoft.com/en-us/library/windows/desktop/ms682425(v=vs.85).aspx

Answer 2

In order to execute a command implemented by the command shell aka cmd.exe , you need to actually run cmd.exe. CreateProcess doesn't automatically do that for you.

Build a command line of the form cmd.exe /c <your command here> . /c means "run one command, then terminate".