23.5 Auto Reverting non-file Buffers

Normally Global Auto Revert Mode only reverts file buffers. There are two ways to auto-revert certain non-file buffers: enabling Auto Revert Mode in those buffers (using M-x auto-revert-mode) and setting global-auto-revert-non-file-buffers to t. The latter enables Auto Reverting for all types of buffers for which it is implemented, that is, for the types of buffers listed in the menu below.

Like file buffers, non-file buffers should normally not revert while you are working on them, or while they contain information that might get lost after reverting. Therefore, they do not revert if they are “modified”. This can get tricky, because deciding when a non-file buffer should be marked modified is usually more difficult than for file buffers.

Another tricky detail is that, for efficiency reasons, Auto Revert often does not try to detect all possible changes in the buffer, only changes that are “major” or easy to detect. Hence, enabling auto-reverting for a non-file buffer does not always guarantee that all information in the buffer is up to date and does not necessarily make manual reverts useless.

At the other extreme, certain buffers automatically auto-revert every auto-revert-interval seconds. (This currently only applies to the Buffer Menu.) In this case, Auto Revert does not print any messages while reverting, even when auto-revert-verbose is non-nil.

The details depend on the particular types of buffers and are explained in the corresponding sections.