bug#8541: start-process fails when both the program path and an argument contain spaces

[Eli Zaretskii <eliz@gnu.org>]

> Date: Sun, 24 Apr 2011 12:01:17 +0200
> From: Ivar Rummelhoff <ivarru@gmail.com>
> 
> 1. Trying to execute
> 
>     (start-process "name" "buffer" "D:\\tmp\\xxx yyy\\foo.bat" "yada yada")
> 
> writes the following to "buffer":
> 
>     'd:\tmp\xxx' is not recognized as an internal or external command,
>     operable program or batch file.
> 
>     Process name exited abnormally with code 1
> 
> Emacs version: GNU Emacs 23.3.1 (i386-mingw-nt6.1.7601) of 2011-03-10 on 3249CTO
> 
> 
> 2. If space is avoided in either the program path or the argument, as in
> 
>     (start-process "name" "buffer" "D:\\tmp\\foo.bat" "yada yada")
> or
>     (start-process "name" "buffer" "D:\\tmp\\xxx yyy\\foo.bat" "yada-yada")
> 
> then everything works well.
> 
> 
> 3. The same problem occurs when I give `start-process' the program
> name only (instead of the full path) as long as the full path to the
> program contains spaces (and one of the arguments contains spaces).
> 
> 
> 4. Quoting the program path or the argument (with " or \) does not
> help. If quote the program path, I get "no such file or directory";
> and quoting the argument has no effect as long as there is still a
> space character "in there". (Besides, it seems any quoting of the
> arguments is passed on to the program.)

This is due to deficiencies in the Windows API for launching programs
(CreateProcess): it concatenates the command arguments into a single
string, separated by blanks..  To work around, invoke the command
through cmd.exe, and use cmd.exe-specific quoting character '^'.  Like
this:

 (start-process "name" "buffer" "cmd.exe" "/c" "D:\\tmp\\xxx^ yyy\\foo.bat yada^ yada")

This is fragile, and you will need to redo the quoting if you invoke
other programs or have whitespace in other places.  But I don't know
how to do better, given the Windows API misfeatures.  It is best to
avoid whitespace in the arguments.  For file names, you can use 8+3
aliases, if you cannot control the names of the files or directories.