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GNU Info (elisp)Read Only BuffersRead-Only Buffers ================= If a buffer is "read-only", then you cannot change its contents, although you may change your view of the contents by scrolling and narrowing. Read-only buffers are used in two kinds of situations: * A buffer visiting a write-protected file is normally read-only. Here, the purpose is to inform the user that editing the buffer with the aim of saving it in the file may be futile or undesirable. The user who wants to change the buffer text despite this can do so after clearing the read-only flag with `C-x C-q'. * Modes such as Dired and Rmail make buffers read-only when altering the contents with the usual editing commands would probably be a mistake. The special commands of these modes bind `buffer-read-only' to `nil' (with `let') or bind `inhibit-read-only' to `t' around the places where they themselves change the text. - Variable: buffer-read-only This buffer-local variable specifies whether the buffer is read-only. The buffer is read-only if this variable is non-`nil'. - Variable: inhibit-read-only If this variable is non-`nil', then read-only buffers and read-only characters may be modified. Read-only characters in a buffer are those that have non-`nil' `read-only' properties (either text properties or overlay properties). Note: Special Properties, for more information about text properties. Note: Overlays, for more information about overlays and their properties. If `inhibit-read-only' is `t', all `read-only' character properties have no effect. If `inhibit-read-only' is a list, then `read-only' character properties have no effect if they are members of the list (comparison is done with `eq'). - Command: toggle-read-only This command changes whether the current buffer is read-only. It is intended for interactive use; do not use it in programs. At any given point in a program, you should know whether you want the read-only flag on or off; so you can set `buffer-read-only' explicitly to the proper value, `t' or `nil'. - Function: barf-if-buffer-read-only This function signals a `buffer-read-only' error if the current buffer is read-only. Note: Interactive Call, for another way to signal an error if the current buffer is read-only. automatically generated by info2www version 1.2.2.9 |