QueryFullProcessImageName not work,return 0 - vba

Question

QueryFullProcessImageName always return 0,can not retrieve process path,code below,need you help,thanks.
Public Declare Function QueryFullProcessImageName Lib "Kernel32.dll" Alias "QueryFullProcessImageNameA" (hProcess As Long, ByVal dwFlags As Long, ByVal lpExeName As String, lpdwSize As Long) As Long
Private Function GetProcessImageName(ByVal lProcessID As Long) As String
Dim hProcess As Long
Dim sBuf As String
Dim sChar As Long
hProcess = OpenProcess(PROCESS_QUERY_LIMITED_INFORMATION Or PROCESS_QUERY_INFORMATION, 0, lProcessID)
If hProcess Then
sBuf = String$(MAX_PATH, Chr$(0))
QueryFullProcessImageName hProcess, 0, sBuf, MAX_PATH
sBuf = Left$(sBuf, sChar)
End If
GetProcessImageName = sBuf
CloseHandle hProcess
End Function

Answer 1

if you use the GetLastError Function you'll be able to get more information of why it returns 0.

Answer 2

There are a couple issues in the code.
First, sChar is never initialized.
Also, the first parameter to QueryFullProcessImageName is an "In" param so it should be passed ByVal. That may be the cause of the invalid handle error 6.
This thread has some helpful information about how to get the length back when calling QueryFullProcessImageName: http://www.vbforums.com/showthread.php?805537-RESOLVED-Excel-Crash-when-call-API-function-QueryFullProcessImageName-in-excel-VBA-of-win7.
Finally, per https://msdn.microsoft.com/en-us/library/windows/desktop/ms684880(v=vs.85).aspx, "A handle that has the PROCESS_QUERY_INFORMATION access right is automatically granted PROCESS_QUERY_LIMITED_INFORMATION", so remove the unneeded access right.
With that info, try something like this (untested):
Public Declare Function QueryFullProcessImageName Lib "Kernel32.dll" Alias "QueryFullProcessImageNameA" _
(ByVal hProcess As Long, ByVal dwFlags As Long, ByVal lpExeName As String, ByRef lpdwSize As Long) As Long
Private Function GetProcessImageName(ByVal lProcessID As Long) As String
Dim hProcess As Long
Dim sBuf As String
Dim sChar As Long
hProcess = OpenProcess(PROCESS_QUERY_INFORMATION, 0, lProcessID)
If hProcess Then
sBuf = String$(MAX_PATH, Chr$(0))
sChar = MAX_PATH
QueryFullProcessImageName hProcess, 0, sBuf, sChar
sBuf = Left$(sBuf, sChar)
End If
GetProcessImageName = sBuf
CloseHandle hProcess
End Function