How to run child C/C++ defrag process?

Question

C++ / C#

There is a console menu.
You need to start a child process with parameters. Here is an attempt to defragment drive C. What's wrong?
spawnl(P_WAIT,"defrag","C",NULL);
UPD:

#include "stdafx.h"
#include "windows.h"

void main()
{
  STARTUPINFO cif;
  ZeroMemory(&cif,sizeof(STARTUPINFO));
  PROCESS_INFORMATION pi;
  CreateProcess(L"c:\\windows\\system32\\defrag.exe",NULL,
    NULL,NULL,FALSE,NULL,NULL,NULL,&cif,&pi);
}

But how to pass the disk parameter?

Answer 1

You better know what's wrong. It would be nice to specify the expected and actual behavior. I assume that specifying the absolute path to the file will solve the problem. You can also look at CreateProcess in order not to use any wrappers.