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author | Richard M. Stallman <rms@gnu.org> | 1997-08-22 05:58:17 +0000 |
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committer | Richard M. Stallman <rms@gnu.org> | 1997-08-22 05:58:17 +0000 |
commit | 8b8607ed9654d1d79b4e35721ffac24a8d5a4612 (patch) | |
tree | 8ec634ea827869e3a5f2966795fd4563d8753ff4 | |
parent | 22346e47e7a7316a1cd05eb8c41f39fb0dbaedc4 (diff) | |
download | emacs-8b8607ed9654d1d79b4e35721ffac24a8d5a4612.tar.gz |
Explain after-change-functions and chars vs bytes.
-rw-r--r-- | lispref/text.texi | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/lispref/text.texi b/lispref/text.texi index 6ba44ecda1a..2780eb56452 100644 --- a/lispref/text.texi +++ b/lispref/text.texi @@ -2973,9 +2973,16 @@ buffer that is about to change is always the current buffer. This variable holds a list of a functions to call after any buffer modification. Each function receives three arguments: the beginning and end of the region just changed, and the length of the text that existed -before the change. (To get the current length, subtract the region -beginning from the region end.) All three arguments are integers. The -buffer that's about to change is always the current buffer. +before the change. All three arguments are integers. The buffer that's +about to change is always the current buffer. + +The length of the old text is measured in bytes; it is the difference +between the buffer positions before and after that text, before the +change. As for the changed text, its length in bytes is simply the +difference between the first two arguments. If you want the length +in @emph{characters} of the text before the change, you should use +a @code{before-change-functions} function that calls @code{chars-in-region} +(@pxref{Chars and Bytes}). @end defvar @defvar before-change-function |