From b047e7acb5d18ccabb7548e3e7d79eba711008bf Mon Sep 17 00:00:00 2001 From: Paul Eggert Date: Fri, 3 Jun 2011 11:47:14 -0700 Subject: [PATCH] Document wide integers better. * buffers.texi (Buffers): * files.texi (Visiting): Default buffer maximum is now 2 EiB typically. --- doc/emacs/ChangeLog | 6 ++++++ doc/emacs/buffers.texi | 7 +++++-- doc/emacs/files.texi | 3 ++- 3 files changed, 13 insertions(+), 3 deletions(-) diff --git a/doc/emacs/ChangeLog b/doc/emacs/ChangeLog index 89a78263e9..3b61ca6ccb 100644 --- a/doc/emacs/ChangeLog +++ b/doc/emacs/ChangeLog @@ -1,3 +1,9 @@ +2011-06-02 Paul Eggert + + Document wide integers better. + * buffers.texi (Buffers): + * files.texi (Visiting): Default buffer maximum is now 2 EiB typically. + 2011-05-28 Chong Yidong * custom.texi (Hooks): Reorganize. Mention Prog mode. diff --git a/doc/emacs/buffers.texi b/doc/emacs/buffers.texi index ae0d85f249..9463b02464 100644 --- a/doc/emacs/buffers.texi +++ b/doc/emacs/buffers.texi @@ -43,8 +43,11 @@ can be different from the value in other buffers. @xref{Locals}. A buffer's size cannot be larger than some maximum, which is defined by the largest buffer position representable by the @dfn{Emacs integer} data type. This is because Emacs tracks buffer positions -using that data type. For 32-bit machines, the largest buffer size is -512 megabytes. +using that data type. For most machines, the maximum buffer size +enforced by the data types is @math{2^61 - 2} bytes, or about 2 EiB. +For some older machines, the maximum is @math{2^29 - 2} bytes, or +about 512 MiB. Buffer sizes are also limited by the size of Emacs's +virtual memory. @menu * Select Buffer:: Creating a new buffer or reselecting an old one. diff --git a/doc/emacs/files.texi b/doc/emacs/files.texi index 40bd065610..793a11e62e 100644 --- a/doc/emacs/files.texi +++ b/doc/emacs/files.texi @@ -209,7 +209,8 @@ to reread it. about 10 megabytes), Emacs asks you for confirmation first. You can answer @kbd{y} to proceed with visiting the file. Note, however, that Emacs cannot visit files that are larger than the maximum Emacs buffer -size, which is around 512 megabytes on 32-bit machines +size, which is limited by the amount of memory Emacs can allocate +and by the integers that Emacs can represent (@pxref{Buffers}). If you try, Emacs will display an error message saying that the maximum buffer size has been exceeded. -- 2.20.1