From: Lars Ingebrigtsen <larsi@gnus.org>
Date: Sun, 13 Jun 2021 12:14:32 +0000 (+0200)
Subject: Fsubstitute_in_file_name doc string clarification
X-Git-Tag: emacs-28.0.90~2132
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=c4fcf2fc6fbdddb1da2ec1166bf95bfb72baff1a;p=emacs.git

Fsubstitute_in_file_name doc string clarification

* src/fileio.c (Fsubstitute_in_file_name): Mention that undefined
variables aren't replaced (as opposed to what happens in a shell
substitution) (bug#40949).
---

diff --git a/src/fileio.c b/src/fileio.c
index caf077e2fbf..1d9a3e16444 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -1830,6 +1830,8 @@ the value of that variable.  The variable name should be terminated
 with a character not a letter, digit or underscore; otherwise, enclose
 the entire variable name in braces.
 
+If FOO is not defined in the environment, it is not substituted.
+
 If `/~' appears, all of FILENAME through that `/' is discarded.
 If `//' appears, everything up to and including the first of
 those `/' is discarded.  */)