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Running Python (Windows) with _spawnvp requires unexpected quotesaround arguments

Tim Peters tim.one at comcast.net
Sun Oct 26 12:37:57 EST 2003 
[Elmar Krieger]
> The _spawnvp function expects the command line arguments as a NULL
> terminated list of char * pointers,

That's true.

> hence there is no need to enclose filenames with quotes if they
> contain spaces.

But that's not true, on Windows.  The Microsoft implementation of the spawn
functions uses the Win32 CreateProcess(), which doesn't take an array of
arguments -- it takes a pointer to a single command line string.  The MS
implementation pastes all the arguments into that single string before
calling CreateProcess(), replacing the terminating NUL character in each
argument with a single blank (except the last argument, whose terminating
NUL is left alone, and so serves as the terminating NUL character of the
command line string).  CreateProcess() in turn then can't tell the
difference between a blank inserted by a spawn function and a blank
originally present in one of your arguments.

> However, if I run pythonw.exe with _spawnvp, and the Python script to
> execute (that's the second command line parameter) has spaces in the
> pathname, it only works if the pathname is enclosed with quotes.
> Is that OK?

That is how it works.
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