C#

bool seen2=false;
foreach(char c in s) {
    if (c=='2') seen2=true;
    else if (c=='4') return seen2;
}
return false;

bool seen2=false;
foreach(char c in s) {
    if (c=='2') seen2=true;
    else if (c=='4' && seen2) return true;
}
return false;

string str = new string(buffer).TrimEnd('\0');

string str = new string(buffer, 0, length);

        /* http://msdn.microsoft.com/en-us/library/ms893424.aspx
  VOID FAR PASCAL lineCallbackFunc( 
  DWORD hDevice, 
  DWORD dwMsg, 
  DWORD dwCallbackInstance, 
  DWORD dwParam1, 
  DWORD dwParam2, 
  DWORD dwParam3
);*/
        private delegate void lineCallbackFunc(
            uint hDevice,
            uint dwMsg,
            uint dwCallbackInstance,
            uint dwParam1,
            uint dwParam2,
            uint dwParam3);

        /* http://msdn.microsoft.com/en-us/library/ms894378.aspx
typedef struct lineinitializeexparams_tag {
  DWORD dwTotalSize;
  DWORD dwNeededSize;
  DWORD dwUsedSize;
  DWORD dwOptions;
  union {
    HANDLE hEvent;
    HANDLE hCompletionPort;
  } Handles;
  DWORD dwCompletionKey;
} LINEINITIALIZEEXPARAMS, FAR* LPLINEINITIALIZEEXPARAMS;*/

        [StructLayout(LayoutKind.Sequential)]
        private struct LINEINITIALIZEEXPARAMS
        {
            public uint dwTotalSize;
            public uint dwNeededSize;
            public uint dwUsedSize;
            public uint dwOptions;
            public IntPtr hEvent;
            public IntPtr hCompletionPort;
            public uint dwCompletionKey;
        }


        /* http://msdn.microsoft.com/en-us/library/ms894370.aspx
  LONG WINAPI lineInitializeEx(
  LPHLINEAPP lphLineApp,
  HINSTANCE hInstance,
  LINECALLBACK lpfnCallback,
  LPCWSTR lpszFriendlyAppName,
  LPDWORD lpdwNumDevs,
  LPDWORD lpdwAPIVersion,
  LPLINEINITIALIZEEXPARAMS lpLineInitializeExParams
);*/
        [DllImport("cellcore.dll", SetLastError = true)]
        private static extern uint lineInitializeEx(
            out IntPtr lphLineApp, // edit: this is a pointer to a handle so added 'out'
            IntPtr hInstance,
            lineCallbackFunc lpfnCallback,
            StringBuilder lpszFriendlyAppName,
            out uint lpdwNumDevs,
            out uint lpdwAPIVersion,
            ref LINEINITIALIZEEXPARAMS lpLineInitializeExParams
            );

[StructLayout(LayoutKind.Explict)]
private struct LINEINITIALIZEEXPARAMS
{
    [FieldOffset(0)]
    public uint dwTotalSize;
    [FieldOffset(4)]
    public uint dwNeededSize;
    [FieldOffset(8)]
    public uint dwUsedSize;
    [FieldOffset(12)]
    public IntPtr hEvent;
    public IntPtr hCompletionPort;
    [FieldOffset(12)]
    public uint dwCompletionKey;
}

DaveyM69 wrote:

[FieldOffset(12)]
public uint dwCompletionKey;

typedef struct lineinitializeexparams_tag {
  DWORD dwTotalSize;
  DWORD dwNeededSize;
  DWORD dwUsedSize;
  DWORD dwOptions;
  union {
    HANDLE hEvent;
    HANDLE hCompletionPort;
  } Handles;
  DWORD dwCompletionKey;
} LINEINITIALIZEEXPARAMS, *LPLINEINITIALIZEEXPARAMS;