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I don't understand this comment on message2
From: |
Kim F. Storm |
Subject: |
I don't understand this comment on message2 |
Date: |
Mon, 19 Sep 2005 10:30:56 +0200 |
User-agent: |
Gnus/5.11 (Gnus v5.11) Emacs/22.0.50 (gnu/linux) |
I have studied the code in message2 and the functions called by it
quite a lot (hunting for GC-related errors), and I don't understand
the restrictions in the second paragraph of message2's commentary
(included below).
It is indeed not safe to pass data from a lisp string (due to
potential GC), but not for the reasons listed. I cannot find any
place where the buffer M is stored for later reference.
So using alloca'ed memory seems safe to me.
Can anyone enlighten me?
/* Display an echo area message M with a specified length of NBYTES
bytes. The string may include null characters. If M is 0, clear
out any existing message, and let the mini-buffer text show
through.
The buffer M must continue to exist until after the echo area gets
cleared or some other message gets displayed there. This means do
not pass text that is stored in a Lisp string; do not pass text in
a buffer that was alloca'd. */
void
message2 (m, nbytes, multibyte)
--
Kim F. Storm <address@hidden> http://www.cua.dk
- I don't understand this comment on message2,
Kim F. Storm <=