Re: call-process having problems with a big total length of arguments under Windows

[Mathias Dahl <mathias.dahl@gmail.com>]

PS. I found a limit on the number of arguments I can use if the
argument is one character:

(apply 'call-process
       (append (list
                "ping"
                nil t nil)
               (make-list 16369 "1")))

Now, if I double the length of each argument I can get higher than
16369 characters in total:

(apply 'call-process
       (append (list
                "ping"
                nil t nil)
               (make-list 10912 "12")))

So, it's not simply the total amount, but a combination of the number
of arguments on the length of those arguments.

Any ideas?

On Sun, Mar 10, 2013 at 2:02 PM, Mathias Dahl <mathias.dahl@gmail.com> wrote:
> Under GNU/Linux I can do this (calling ping with an 10000 long argument list):
>
> (apply 'call-process
>        (append (list
>                 "ping"
>                 nil t nil)
>                (make-list 10000 "0123456789")))
>
> (of course, ping complains about the syntax, but that is another
> matter, ping is just an example of a command that exists on both
> platforms where I test)
>
> On Windows (Windows 7, 64 bit) this works in a quite recent Emacs
> (24.1.50.1 from last summer):
>
> (apply 'call-process
>        (append (list
>                 "ping"
>                 nil t nil)
>                (make-list 2000 "0123456789")))
>
> But this does not (2000 is changed to 3000):
>
> (apply 'call-process
>        (append (list
>                 "ping"
>                 nil t nil)
>                (make-list 3000 "0123456789")))
>
> I get (file-error "Spawning child process" "exec format error") when I
> reach a certain amount of arguments. I can make it fail at fewer
> arguments if I make the length of each argument longer.
>
> What sets the limit here? Is there a bug in Emacs on Windows or is it
> a limitation of the OS? Is there is a known limitation in the total
> length of all parameters?
>
> Thanks!
>
> /Mathias