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authorNoam Postavsky <npostavs@gmail.com>2016-07-10 21:52:23 -0400
committerNoam Postavsky <npostavs@gmail.com>2016-07-14 20:01:39 -0400
commit9ba51edf62b25c678508a316ec78a09b18d3bf9e (patch)
tree99f1e4e776bc3814a41164d41a8c10dbfe425b0d
parent452aa949bc4de77b1fba103de6b61e55b2ca8c0b (diff)
Document buffer-swap-text+save-excursion interaction
* doc/lispref/buffers.texi (Swapping Text): * src/buffer.c (Fbuffer_swap_text): Add warning about interaction of `buffer-swap-text' and `save-excursion' (Bug #4655).
-rw-r--r--doc/lispref/buffers.texi6
-rw-r--r--src/buffer.c4
2 files changed, 9 insertions, 1 deletions
diff --git a/doc/lispref/buffers.texi b/doc/lispref/buffers.texi
index 1f7f263fb2..740d7cfd8a 100644
--- a/doc/lispref/buffers.texi
+++ b/doc/lispref/buffers.texi
@@ -1211,6 +1211,12 @@ swapped as well: the positions of point and mark, all the markers, the
overlays, the text properties, the undo list, the value of the
@code{enable-multibyte-characters} flag (@pxref{Text Representations,
enable-multibyte-characters}), etc.
+
+@strong{Warning:} If this function is called from within a
+@code{save-excursion} form, the current buffer will be set to
+@var{buffer} upon leaving the form, since the marker used by
+@code{save-excursion} to save the position and buffer will be swapped
+as well.
@end defun
If you use @code{buffer-swap-text} on a file-visiting buffer, you
diff --git a/src/buffer.c b/src/buffer.c
index e4269c0046..89f4479740 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -2231,7 +2231,9 @@ advance_to_char_boundary (ptrdiff_t byte_pos)
DEFUN ("buffer-swap-text", Fbuffer_swap_text, Sbuffer_swap_text,
1, 1, 0,
- doc: /* Swap the text between current buffer and BUFFER. */)
+ doc: /* Swap the text between current buffer and BUFFER.
+Using this function from `save-excursion' might produce surprising
+results, see Info node `(elisp)Swapping Text'. */)
(Lisp_Object buffer)
{
struct buffer *other_buffer;