I have tried translating VB code to Ruby which tells if a process with given
pid is running on Win 2K.
The VB code works. But my translated Ruby code does not. What am I missing ?

I suspect my assigment to uProcess in the code below.

I using ruby 1.7.3 (2002-11-17) [i386-mswin32]

TIA,
-- shanko

=begin

Public Type PROCESSENTRY32
    dwSize As Long
    cntUsage As Long
    th32ProcessID As Long ' This process
    th32DefaultHeapID As Long
    th32ModuleID As Long ' Associated exe
    cntThreads As Long
    th32ParentProcessID As Long ' This process's parent process
    pcPriClassBase As Long ' Base priority of process threads
    dwFlags As Long
    szExeFile As String * 260 ' MAX_PATH
End Type

Dim uProcess As PROCESSENTRY32

=end

require 'Win32API'

STDOUT.sync = true

PROCESSENTRY32_SIZE = 296

def process_running?(pid,ppid = -1)
params = [ 'L', # IN DWORD dwFlags
              'L' # IN DWORD th32ProcessID
            ]
retVal = 'L' # HANDLE
getProcessSnapShot = Win32API.new("kernel32", "CreateToolhelp32Snapshot",
params, retVal)
hProcess = getProcessSnapShot.call(8,0)

params = [ 'L', # hSnapshot [in] Handle to the snapshot returned from a
previous call to the CreateToolhelp32Snapshot function.
              'P' # lppe [in, out] Pointer to a PROCESSENTRY32 structure
            ]
retVal = 'I' # BOOL

# uProcess.dwSize = Len(uProcess) <<< how to translate this line of VB code
in Ruby ?

uProcess = [PROCESSENTRY32_SIZE].pack('I') + ([0].pack('I') *
(PROCESSENTRY32_SIZE - 4))

getProcessFirst = Win32API.new("kernel32", "Process32First", params,
retVal)
getProcessNext = Win32API.new("kernel32", "Process32Next", params,
retVal)

r = getProcessFirst.call(hProcess,uProcess)
found = false
while (r != 0)
    puts r
    gotPid = uProcess.th32ProcessID
    gotPpid = uProcess.th32ParentProcessID
    (found = true; break) if (gotPid == pid) and ((ppid >= 0) ? (ppid ==
gotPpid) : true)
    r = getProcessNext.call(hProcess,uProcess)
end

found
end

if $0 == __FILE__
    puts process_running?(1792)
end