Improve documentation of set-default-file-modes

* src/fileio.c (Fset_default_file_modes): Doc fix.  (Bug#28875)

* doc/lispref/files.texi (Changing Files): Clarify how the bits in
the argument of set-default-file-modes are used for setting file
permissions.

1 files changed, 3 insertions, 1 deletions

diff --git a/doc/lispref/files.texi b/doc/lispref/files.texi
index f49b02de97c..254eab03ea5 100644
--- a/doc/lispref/files.texi
+++ b/doc/lispref/files.texi
@@ -1821,7 +1821,9 @@ has these permissions, or a subset of them (@code{write-region} will
 not grant execute permissions even if the default file permissions
 allow execution).  On GNU and other POSIX-like systems, the default
 permissions are given by the bitwise complement of the @samp{umask}
-value.
+value, i.e.@: each bit that is set in the argument @var{mode} will be
+@emph{reset} in the default permissions with which Emacs creates
+files.
 
 The argument @var{mode} should be an integer which specifies the
 permissions, similar to @code{set-file-modes} above.  Only the lowest