How do I stop Py_Initialise crashing the application?

From VBA and VB6 I'm calling a dll the creates a Python 开发者_运维知识库interpreter. If I set the PATH environment variable to point to "C:\python27" and PYTHONPATH to "c:\python27\lib" all is fine.

If I don't set the PATH then calling Py_Initialise() crashes XL or my VB6 app, even if I call Py_SetProgramName with "c:\python27\python27.exe" first.

I'd like to specify the installation in VB/VBA rather than having it set in the environment as I can't do that in XL (works ok for VB6).

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The best answer I've found so far is that it is a bug in Python - http://bugs.python.org/issue6498. The intepreter seems to call exit() on certain errors rather than passing a code back to the caller. Not very friendly if you're embedding python in an app. But there you go.

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try to change the working directory before calling the dll:

In your VBA code:

chdir("c:\python27\") '- change the working-directory for python
=> call dll '- call the dll
chdir(app.Path) '- change back to your folder (maybe you want to save your current folder bevore you change it the first time and change back to this?!)

regards Thomas

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You can simply check if the needed environment variable is set:

dim PPath as string
PPath = trim(Environ("PYTHONPATH"))
if (PPath<>"")
  <call dll>
else
  msgbox ("Error!")
end if

Or you can run the dll in a nother Test-Process: if this call works you know that it is OK to call the dll - it depends on the DLL call your using so I'm not sure about that:

Private Declare Function CloseHandle Lib "kernel32" (ByVal _
    hObject As Long) As Long

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

Const STILL_ACTIVE = &H103
Const PROCESS_ALL_ACCESS = &H1F0FFF

...
dim IsActive as boolean
dim Handle as long
Dim TaskID As Long
TaskID = Shell("rundll32.exe pyton.dll Py_Initialise()", vbNormalNoFocus)

<wait for some time>

'- check if pyton.dll is still running
Handle = OpenProcess(PROCESS_ALL_ACCESS, False, TaskID)
Call GetExitCodeProcess(Handle, ExitCode)
Call CloseHandle(Handle)

IsActive = IIf(ExitCode = STILL_ACTIVE, True, False)

if (not IsActive) then
  msgbox ("Error!")
else
  <kill process>
  <call dll normally>
end if

Regards Thomas