Fredrik Lundh wrote:
> the definition of sys.executable is a bit unclear, something that has led to
> incompatible use in deployed code.
>
> the docstring for sys.executable says "pathname of this Python interpreter",
> which can be interpreted as either
>
> a) sys.executable points to the executable that was used to load the
> Python interpreter library/dll.
>
> this use is supported by the docstring and the implementation, and is
> quite
> common in the wild. an application using this interpretation may
>
> - call sys.executable to run another instance of itself
> - extract data from resources embedded in (or attached to) sys.executable
> - locate configuration data etc via os.path.dirname(sys.executable)
>
> etc.
>
> or
>
> b) sys.executable points to a standard Python interpreter executable of
> the same version, and having the same library, as the currently running
> interpreter instance.
>
> this use is supported by more strict interpretation of the word
> "interpreter"
> (as an executable, rather than an implementation DLL), and is quite common
> in the wild. an application using this interpretation may
>
> - call sys.executable to run a Python script in the same environment as
> itself.
>
> etc.
>
> or
>
> c) sys.executable points to the file containing the actual ("this")
> interpreter. I
> haven't seen any code that assumes this, probably because no
> implementation
> uses this interpretation...
>
> for programs that are invoked via the standard interpreter, case (a) and (b)
> are of
> course identical.
py2exe used the a) interpretation. It uses sys.executable to find the exe that
is currently
running, for registration of COM servers, and for finding resources in the exe:
the manifest
file that's needed for GUI applications on WindowsXP to give the native XP look
and feel,
icons, typelibs, and more.
> the problem is when the interpreter library is embedded in some other
> application;
> should sys.executable be set to the actual EXE used to start the program, or
> to
> something else ? if it's set to something else, how can that application do
> the things
> that's described under (a) ?
The use case for b) 'call sys.executable to run a Python script' makes no sense
for
a py2exe'd application.
Thomas
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