File names encoding when running shell-command on Windows XP

Question

I faced a problem when pdflatex launched from Emacs couldn't compile files whose name contained Russian characters. The same code worked on Linux, so I suspected that something is wrong with encoding of file name. OS: Windows XP, file system encoding is cp-1251, Emacs: 24.5.1.

I created 2 files:

• D:/Russia.tex
• D:/Россия.tex

Then I tried this:

;works fine, produces Russia.pdf
(shell-command "pdflatex D:/Russia.tex")

;doesn't work. TeX error: I can't find file `D:/Россия.tex'
(shell-command "pdflatex D:/Россия.tex")

Then I tried to convert the Russian name to cp-1251:

;This works, but hard-coded 'cp1251 is bad
(setq file-name (encode-coding-string "D:/Россия.tex" 'cp1251))
(shell-command (concat "pdflatex " file-name))

This code has 1 defect - the file system encoding is hard-coded. Encoding and I/O page says that there is a variable file-name-coding-system --- "specifies the coding system to use for encoding file names". But it is nil for me.

Also the fact that utf-8 code doesn't work is weird as the page says:

On Windows 2000 and later, Emacs by default uses Unicode APIs to pass file names to the OS, so the value of file-name-coding-system is largely ignored. Lisp applications that need to encode or decode file names on the Lisp level should use utf-8 coding-system when system-type is windows-nt; the conversion of UTF-8 encoded file names to the encoding appropriate for communicating with the OS is performed internally by Emacs.

Maybe this note about utf-8 is not applicable to shell-command? How to get the encoding of the file system?

Answer 1

For windows in ru environment I have the following:

(setq default-process-coding-system '(utf-8-dos . cp1251-dos))

It let's me process files in russian from emacs using external shell invocations AND I can also use grep, ripgrep and friends to search for russian text.

Answer 2

In ~/.emacs we set the variable with fs encoding:

(defvar *fs-encoding* 'cp1251)

When we need to get the encoded file name, we use function get-file-name:

(defun get-file-name (file-name)
  "get file name of the buffer, encode if necessary"
    (when *fs-encoding*
      (shell-quote-argument (encode-coding-string file-name *fs-encoding*)))
    )

(setq file-name (get-file-name "D:/Россия.tex"))
(shell-command (concat "pdflatex " file-name))