Unzip .gz files - excel

Question

I have a folder with 30 or so .gz zipped files and 1 .zip files. I can ue code to utilise Windows Explorer to unzip the 1 .zip file, but unfortunately, Windows explorer does not unzip .gz files. I have created code which utilises Winzip to open all these files, but unfortunately this opens up the path folder, every time it unzips, I end up with 30+ open folders, which I then close, one by one with further code - unnecessary. A process that takes near 10 minutes.
Scouring the net, I've found and adapted a Ron De Bruin code that utilises '7-zip' software , open source and freely available online, to unzip without opening up a new folder each time. It unzips all files effortlessly in about a minute, far better. The code is below (mainly comments so not as long as it first looks!). My only problem is that sometimes this unzips files, and sometimes this runs without unzipping any files. When it runs perfectly, it toggles the 'GetExitCodePorcess hProcess, ExitCode' line longer, there I'm assuming it is processes to get an ExitCode which allows it to unzip the file. When it isn't working, it only toggles once or twice and moves onto the next stage, therefore, I assume that it generated the wrong exit code.
Is the problem the PtrSafe Function? Or is it in my ShellStr, or anywhere else? Please help, as I want to avoid using the Winzip method. If anyone has any other alternatives, please suggest!
#If VBA7 Then
Private Declare PtrSafe Function OpenProcess Lib "kernel32" _
(ByVal dwDesiredAccess As Long, _
ByVal bInheritHandle As Long, _
ByVal dwProcessId As Long) As Long
Private Declare PtrSafe Function GetExitCodeProcess Lib "kernel32" _
(ByVal hProcess As Long, _
lpExitCode As Long) As Long
#Else
Private Declare Function OpenProcess Lib "kernel32" _
(ByVal dwDesiredAccess As Long, _
ByVal bInheritHandle As Long, _
ByVal dwProcessId As Long) As Long
Private Declare Function GetExitCodeProcess Lib "kernel32" _
(ByVal hProcess As Long, _
lpExitCode As Long) As Long
#End If
Public Const PROCESS_QUERY_INFORMATION = &H400
Public Const STILL_ACTIVE = &H103
Public Sub ShellAndWait(ByVal PathName As String, Optional WindowState)
Dim hProg As Long
Dim hProcess As Long, ExitCode As Long
'fill in the missing parameter and execute the program
If IsMissing(WindowState) Then WindowState = 1
hProg = Shell(PathName, WindowState)
'hProg is a process ID under Win32. To get the process handle:
hProcess = OpenProcess(PROCESS_QUERY_INFORMATION, False, hProg)
Do
'populate Exitcode variable
GetExitCodeProcess hProcess, ExitCode
DoEvents
Loop While ExitCode = STILL_ACTIVE
End Sub
'With this example you unzip a fixed zip file: FileNameZip = "C:\Users\Ron\Test.zip"
'Note this file must exist, this is the only thing that you must change before you test it
'The zip file will be unzipped in a new folder in: Application.DefaultFilePath
'Normal if you have not change it this will be your Documents folder
'The name of the folder that the code create in this folder is the Date/Time
'You can change this folder to this if you want to use a fixed folder:
'NameUnZipFolder = "C:\Users\Ron\TestFolder\"
'Read the comments in the code about the commands/Switches in the ShellStr
Public Sub B_UnZip_Zip_File_Fixed()
Dim PathZipProgram As String, FolderPath As String
Dim UnzipFile As Variant, ShellStr As String
FolderPath = _
ThisWorkbook.Path
If Right(FolderPath, 1) <> "\" Then
FolderPath = FolderPath & "\"
End If
'Path of the Zip program
PathZipProgram = "C:\program files\7-Zip\"
If Right(PathZipProgram, 1) <> "\" Then
PathZipProgram = PathZipProgram & "\"
End If
'Check if this is the path where 7z is installed.
If Dir(PathZipProgram & "7z.exe") = "" Then
MsgBox "Please find your copy of 7z.exe and try again"
Exit Sub
End If
UnzipFile = _
Dir(FolderPath & "*.gz")
While UnzipFile <> _
""
If InStr(1, UnzipFile, ".gz") > _
0 Then
ShellStr = PathZipProgram & "7z.exe e -aoa -r" _
& " " & Chr(34) & UnzipFile & Chr(34) _
& " -o" & Chr(34) & FolderPath & Chr(34) & " " & "*.*"
ShellAndWait ShellStr, vbHide
End If
UnzipFile = _
Dir
Wend
'Create path and name of the normal folder to unzip the files in
'In this example we use: Application.DefaultFilePath
'Normal if you have not change it this will be your Documents folder
'The name of the folder that the code create in this folder is the Date/Time
'NameUnZipFolder = Application.DefaultFilePath & "\" & Format(Now, "yyyy-mm-dd h-mm-ss")
'You can also use a fixed path like
'NameUnZipFolder = "C:\Users\Ron\TestFolder\"
'Name of the zip file that you want to unzip (.zip or .7z files)
'FileNameZip = "C:\Users\Ron\Test.zip"
'There are a few commands/Switches that you can change in the ShellStr
'We use x command now to keep the folder stucture, replace it with e if you want only the files
'-aoa Overwrite All existing files without prompt.
'-aos Skip extracting of existing files.
'-aou aUto rename extracting file (for example, name.txt will be renamed to name_1.txt).
'-aot auto rename existing file (for example, name.txt will be renamed to name_1.txt).
'Use -r if you also want to unzip the subfolders from the zip file
'You can add -ppassword if you want to unzip a zip file with password (only .7z files)
'Change "*.*" to for example "*.txt" if you only want to unzip the txt files
'Use "*.xl*" for all Excel files: xls, xlsx, xlsm, xlsb
'MsgBox "Look in " & NameUnZipFolder & " for extracted files"
End Sub

Answer 1

No, the exit code tells you the result of the external process that you spawned. For Windows 0 indicates success, non-zero indicates failure (or something else that meant the process wasn't successful)
So basically for some of .gz files 7zip can't complete successfully. You as the coder need to deal with this likely eventuality.
So your best bet is to print/log the 7zip command that it ran ShellStr and run that yourself manually in a command prompt/dos window to see the reason why.