Mention unibyte issues in insert-file-contents-literally doc string

* lisp/files.el (insert-file-contents-literally): Mention possible
issues with multibyte buffers (bug#50560).

1 files changed, 8 insertions, 1 deletions

diff --git a/lisp/files.el b/lisp/files.el
index 67c4628468b..821be1eb2c6 100644
--- a/lisp/files.el
+++ b/lisp/files.el
@@ -2526,7 +2526,14 @@ A buffer may be modified in several ways after reading into the buffer,
 due to Emacs features such as format decoding, character code
 conversion, `find-file-hook', automatic uncompression, etc.
 
-This function ensures that none of these modifications will take place."
+This function ensures that none of these modifications will take place.
+
+Unlike `find-file-literally', this function does not make the
+buffer unibyte, so if this function is used when handling
+binary (non-character) data, it can be convenient to make the
+buffer unibyte first.  This isn't, strictly speaking, necessary,
+because multibyte buffers can also deal with raw bytes.  See info
+node `(elisp)Character Codes' for details.")
   (let ((format-alist nil)
         (after-insert-file-functions nil)
         (coding-system-for-read 'no-conversion)