``MULti-lingual Enhancement to GNU Emacs'')
Emacs also supports various encodings of these characters used by
-internationalized software, such as word processors, mailers, etc.
+other internationalized software, such as word processors and mailers.
@menu
* International Intro:: Basic concepts of multibyte characters.
@kindex C-h h
@findex view-hello-file
@cindex undisplayable characters
-@cindex ?
-@cindex ??
+@cindex @samp{?} in display
The command @kbd{C-h h} (@code{view-hello-file}) displays the file
@file{etc/HELLO}, which shows how to say ``hello'' in many languages.
-This illustrates various scripts. If the font you're using doesn't have
-characters for all those different languages, you will see some hollow
-boxes instead of characters; see @ref{Fontsets}. On non-windowing
-displays, @samp{?} is displayed in place of the hollow box. More than
-one @samp{?} is displayed for undisplayable characters that are wider
-than one column.
+This illustrates various scripts. If some characters can't be
+displayed on your terminal, they appear as @samp{?} or as hollow boxes
+(@pxref{Undisplayable Characters}).
+
+ Keyboards, even in the countries where these character sets are used,
+generally don't have keys for all the characters in them. So Emacs
+supports various @dfn{input methods}, typically one for each script or
+language, to make it convenient to type them.
+
+@kindex C-x RET
+ The prefix key @kbd{C-x @key{RET}} is used for commands that pertain
+to multibyte characters, coding systems, and input methods.
+
+@ignore
+@c This is commented out because it doesn't fit here, or anywhere.
+@c This manual does not discuss "character sets" as they
+@c are used in Mule, and it makes no sense to mention these commands
+@c except as part of a larger discussion of the topic.
+@c But it is not clear that topic is worth mentioning here,
+@c since that is more of an implementation concept
+@c than a user-level concept. And when we switch to Unicode,
+@c character sets in the current sense may not even exist.
@findex list-charset-chars
@cindex characters in a certain charset
The command @kbd{M-x describe-character-set} prompts for a character
set name and displays information about that character set, including
its internal representation within Emacs.
-
- Keyboards, even in the countries where these character sets are used,
-generally don't have keys for all the characters in them. So Emacs
-supports various @dfn{input methods}, typically one for each script or
-language, to make it convenient to type them.
-
-@kindex C-x RET
- The prefix key @kbd{C-x @key{RET}} is used for commands that pertain
-to multibyte characters, coding systems, and input methods.
+@end ignore
@node Enabling Multibyte
@section Enabling Multibyte Characters
@cindex unibyte operation, and Lisp files
@cindex init file, and non-ASCII characters
@cindex environment variables, and non-ASCII characters
- Multibyte strings are not created during initialization from the
-values of environment variables, @file{/etc/passwd} entries etc.@: that
-contain non-ASCII 8-bit characters. However, Lisp files, when they are
-loaded for running, and in particular the initialization file
-@file{.emacs}, are normally read as multibyte---even with
-@samp{--unibyte}. To avoid multibyte strings being generated by
-non-ASCII characters in Lisp files, put @samp{-*-unibyte: t;-*-} in a
-comment on the first line, or specify the coding system @samp{raw-text}
-with @kbd{C-x @key{RET} c}. Do the same for initialization files for
-packages like Gnus.
+ With @samp{--unibyte}, multibyte strings are not created during
+initialization from the values of environment variables,
+@file{/etc/passwd} entries etc.@: that contain non-ASCII 8-bit
+characters.
+
+ Emacs normally loads Lisp files as multibyte, regardless of whether
+you used @samp{--unibyte}. This includes the Emacs initialization
+file, @file{.emacs}, and the initialization files of Emacs packages
+such as Gnus. However, you can specify unibyte loading for a
+particular Lisp file, by putting @samp{-*-unibyte: t;-*-} in a comment
+on the first line. Then that file is always loaded as unibyte text,
+even if you did not start Emacs with @samp{--unibyte}. The motivation
+for these conventions is that it is more reliable to always load any
+particular Lisp file in the same way. However, you can load a Lisp
+file as unibyte, on any one occasion, by typing @kbd{C-x @key{RET} c
+raw-text @key{RET}} immediately before loading it.
The mode line indicates whether multibyte character support is enabled
in the current buffer. If it is, there are two or more characters (most
Dutch, Spanish, and Vietnamese.
@end quotation
-@cindex fonts, for displaying different languages
- To be able to display the script(s) used by your language environment
-on a windowed display, you need to have a suitable font installed. If
-some of the characters appear as empty boxes, download and install the
-GNU Intlfonts distribution, which includes fonts for all supported
-scripts. @xref{Fontsets}, for more details about setting up your
-fonts.
+@cindex fonts for various scripts
+ To display the script(s) used by your language environment on a
+graphical display, you need to have a suitable font. If some of the
+characters appear as empty boxes, you should install the GNU Intlfonts
+package, which includes fonts for all supported scripts.
+@xref{Fontsets}, for more details about setting up your fonts.
@findex set-locale-environment
@vindex locale-language-names
@cindex locales
Some operating systems let you specify the language you are using by
setting the locale environment variables @env{LC_ALL}, @env{LC_CTYPE},
-and @env{LANG}; the first of these which is nonempty specifies your
-locale. Emacs handles this during startup by invoking the
-@code{set-locale-environment} function, which matches your locale
-against entries in the value of the variable
+or @env{LANG}.@footnote{If more than one of these is set, the first
+one that is nonempty specifies your locale for this purpose.} Emacs
+handles this during startup by matching your locale against entries in
+the value of the variables @code{locale-charset-language-names} and
@code{locale-language-names} and selects the corresponding language
-environment if a match is found. But if your locale also matches an
-entry in the variable @code{locale-charset-language-names}, this entry
-is preferred if its character set disagrees. For example, suppose the
-locale @samp{en_GB.ISO8859-15} matches @code{"Latin-1"} in
-@code{locale-language-names} and @code{"Latin-9"} in
-@code{locale-charset-language-names}; since these two language
-environments' character sets disagree, Emacs uses @code{"Latin-9"}.
-
- If all goes well, the @code{set-locale-environment} function selects
-the language environment, since language is part of locale. It also
-adjusts the display table and terminal coding system, the locale coding
-system, and the preferred coding system as needed for the locale.
-
- Since the @code{set-locale-environment} function is automatically
-invoked during startup, you normally do not need to invoke it yourself.
-However, if you modify the @env{LC_ALL}, @env{LC_CTYPE}, or @env{LANG}
-environment variables, you may want to invoke the
-@code{set-locale-environment} function afterwards.
+environment if a match is found. (The former variable overrides the
+latter.) It also adjusts the display table and terminal coding
+system, the locale coding system, and the preferred coding system as
+needed for the locale.
+
+ If you modify the @env{LC_ALL}, @env{LC_CTYPE}, or @env{LANG}
+environment variables while running Emacs, you may want to invoke the
+@code{set-locale-environment} function afterwards to readjust the
+language environment from the new locale.
-@findex set-locale-environment
@vindex locale-preferred-coding-systems
The @code{set-locale-environment} function normally uses the preferred
coding system established by the language environment to decode system
@code{locale-preferred-coding-systems}, Emacs uses that encoding even
though it might normally use @code{japanese-iso-8bit}.
- The environment chosen from the locale when Emacs starts is
-overidden by any explicit use of the command
-@code{set-language-environment} or customization of
-@code{current-language-environment} in your init file.
+ You can override the language environment chosen at startup with
+explicit use of the command @code{set-language-environment}, or with
+customization of @code{current-language-environment} in your init
+file.
@kindex C-h L
@findex describe-language-environment
are in the minibuffer).
@cindex Leim package
-Input methods are implemented in the separate Leim package, which must
-be installed with Emacs.
+ Input methods are implemented in the separate Leim package: they are
+available only if the system administrator used Leim when building
+Emacs. If Emacs was built without Leim, you will find that no input
+methods are defined.
@node Select Input Method
@section Selecting an Input Method
through 0377 (octal) are not really legitimate in the buffer. The valid
non-ASCII printing characters have codes that start from 0400.
- If you type a self-inserting character in the range 0240
-through 0377, Emacs assumes you intended to use one of the ISO
-Latin-@var{n} character sets, and converts it to the Emacs code
-representing that Latin-@var{n} character. You select @emph{which} ISO
-Latin character set to use through your choice of language environment
+ If you type a self-inserting character in the range 0240 through
+0377, or if you use @kbd{C-q} to insert one, Emacs assumes you
+intended to use one of the ISO Latin-@var{n} character sets, and
+converts it to the Emacs code representing that Latin-@var{n}
+character. You select @emph{which} ISO Latin character set to use
+through your choice of language environment
@iftex
(see above).
@end iftex
@end ifinfo
If you do not specify a choice, the default is Latin-1.
- The same thing happens when you use @kbd{C-q} to enter an octal code
-in this range. If you enter a code in the range 0200 through 0237,
-which forms the @code{eight-bit-control} character set, it is inserted
+ If you insert a character in the range 0200 through 0237, which
+forms the @code{eight-bit-control} character set, it is inserted
literally. You should normally avoid doing this since buffers
containing such characters have to be written out in either the
-@code{emacs-mule} or @code{raw-text} coding system, which is usually not
-what you want.
+@code{emacs-mule} or @code{raw-text} coding system, which is usually
+not what you want.
@node Coding Systems
@section Coding Systems
@cindex escape sequences in files
By default, the automatic detection of coding system is sensitive to
escape sequences. If Emacs sees a sequence of characters that begin
-with an @key{ESC} character, and the sequence is valid as an ISO-2022
-code, the code is determined as one of ISO-2022 encoding, and the file
-is decoded by the corresponding coding system
-(e.g. @code{iso-2022-7bit}).
+with an escape character, and the sequence is valid as an ISO-2022
+code, that tells Emacs to use one of the ISO-2022 encodings to decode
+the file.
- However, there may be cases that you want to read escape sequences in
-a file as is. In such a case, you can set th variable
+ However, there may be cases that you want to read escape sequences
+in a file as is. In such a case, you can set the variable
@code{inhibit-iso-escape-detection} to non-@code{nil}. Then the code
-detection will ignore any escape sequences, and so no file is detected
-as being encoded in some of ISO-2022 encoding. The result is that all
-escape sequences become visible in a buffer.
+detection ignores any escape sequences, and never uses an ISO-2022
+encoding. The result is that all escape sequences become visible in
+the buffer.
The default value of @code{inhibit-iso-escape-detection} is
-@code{nil}, and it is strongly recommended not to change it. That's
-because many Emacs Lisp source files that contain non-ASCII characters
-are encoded in the coding system @code{iso-2022-7bit} in the Emacs
-distribution, and they won't be decoded correctly when you visit those
-files if you suppress the escape sequence detection.
+@code{nil}. We recommend that you not change it permanently, only for
+one specific operation. That's because many Emacs Lisp source files
+that contain non-ASCII characters are encoded in the coding system
+@code{iso-2022-7bit} in the Emacs distribution, and they won't be
+decoded correctly when you visit those files if you suppress the
+escape sequence detection.
@vindex coding
You can specify the coding system for a particular file using the
the buffer using @code{set-buffer-file-coding-system} (@pxref{Specify
Coding}).
- While editing a file, you will sometimes insert characters which
-cannot be encoded with the coding system stored in
-@code{buffer-file-coding-system}. For example, suppose you start with
-an ASCII file and insert a few Latin-1 characters into it. Or you could
-edit a text file in Polish encoded in @code{iso-8859-2} and add to it
-translations of several Polish words into Russian. When you save the
-buffer, Emacs can no longer use the previous value of the buffer's
-coding system, because the characters you added cannot be encoded by
-that coding system.
+ You can insert any possible character into any Emacs buffer, but
+most coding systems can only handle some of the possible characters.
+This means that you can insert characters that cannot be encoded with
+the coding system that will be used to save the buffer. For example,
+you could start with an ASCII file and insert a few Latin-1 characters
+into it, or or you could edit a text file in Polish encoded in
+@code{iso-8859-2} and add to it translations of several Polish words
+into Russian. When you save the buffer, Emacs cannot use the current
+value of @code{buffer-file-coding-system}, because the characters you
+added cannot be encoded by that coding system.
When that happens, Emacs tries the most-preferred coding system (set
by @kbd{M-x prefer-coding-system} or @kbd{M-x
-set-language-environment}), and if that coding system can safely encode
-all of the characters in the buffer, Emacs uses it, and stores its value
-in @code{buffer-file-coding-system}. Otherwise, Emacs pops up a window
-with a list of coding systems suitable for encoding the buffer, and
-prompts you to choose one of those coding systems.
-
- If you insert characters which cannot be encoded by the buffer's
-coding system while editing a mail message, Emacs behaves a bit
-differently. It additionally checks whether the most-preferred coding
-system is recommended for use in MIME messages; if it isn't, Emacs tells
-you that the most-preferred coding system is not recommended and prompts
-you for another coding system. This is so you won't inadvertently send
-a message encoded in a way that your recipient's mail software will have
-difficulty decoding. (If you do want to use the most-preferred coding
-system, you can type its name to Emacs prompt anyway.)
+set-language-environment}), and if that coding system can safely
+encode all of the characters in the buffer, Emacs uses it, and stores
+its value in @code{buffer-file-coding-system}. Otherwise, Emacs
+displays a list of coding systems suitable for encoding the buffer's
+contents, and asks to choose one of those coding systems.
+
+ If you insert the unsuitable characters in a mail message, Emacs
+behaves a bit differently. It additionally checks whether the
+most-preferred coding system is recommended for use in MIME messages;
+if it isn't, Emacs tells you that the most-preferred coding system is
+not recommended and prompts you for another coding system. This is so
+you won't inadvertently send a message encoded in a way that your
+recipient's mail software will have difficulty decoding. (If you do
+want to use the most-preferred coding system, you can type its name to
+Emacs prompt anyway.)
@vindex sendmail-coding-system
When you send a message with Mail mode (@pxref{Sending Mail}), Emacs has
C-w} to specify a new file name for that buffer.
@vindex locale-coding-system
- The variable @code{locale-coding-system} specifies a coding system to
-use when encoding and decoding system strings such as system error
-messages and @code{format-time-string} formats and time stamps. This
-coding system should be compatible with the underlying system's coding
-system, which is normally specified by the first environment variable in
-the list @env{LC_ALL}, @env{LC_CTYPE}, @env{LANG} whose value is
-nonempty.
+ The variable @code{locale-coding-system} specifies a coding system
+to use when encoding and decoding system strings such as system error
+messages and @code{format-time-string} formats and time stamps. You
+should choose a coding system that is compatible with the underlying
+system's text representation, which is normally specified by one of
+the environment variables @env{LC_ALL}, @env{LC_CTYPE}, and
+@env{LANG}. (The first one whose value is nonempty is the one that
+determines the text representation.)
@node Fontsets
@section Fontsets
course, Emacs fontsets can use only the fonts that the X server
supports; if certain characters appear on the screen as hollow boxes,
this means that the fontset in use for them has no font for those
-characters.@footnote{The installation instructions have information on
+characters.@footnote{The Emacs installation instructions have information on
additional font support.}
Emacs creates two fontsets automatically: the @dfn{standard fontset}
@node Undisplayable Characters
@section Undisplayable Characters
-Your terminal may not be able to display some non-@sc{ascii} characters.
-Most non-windowing terminals can only use a single character set,
-specified by the variable @code{default-terminal-coding-system}
-(@pxref{Specify Coding}) and characters which can't be encoded in it are
-displayed as @samp{?} by default. Windowing terminals may not have the
-necessary font available to display a given character and display a
-hollow box instead. You can change the default behavior.
+ Your terminal may be unable to display some non-@sc{ascii}
+characters. Most non-windowing terminals can only use a single
+character set (use the variable @code{default-terminal-coding-system}
+(@pxref{Specify Coding}) to tell Emacs which one); characters which
+can't be encoded in that coding system are displayed as @samp{?} by
+default.
+
+ Windowing terminals can display a broader range of characters, but
+you may not have fonts installed for all of them; characters that have
+no font appear as a hollow box.
-If you use Latin-1 characters but your terminal can't display Latin-1,
-you can arrange to display mnemonic @sc{ascii} sequences instead, e.g.@:
-@samp{"o} for o-umlaut. Load the library @file{iso-ascii} to do this.
+ If you use Latin-1 characters but your terminal can't display
+Latin-1, you can arrange to display mnemonic @sc{ascii} sequences
+instead, e.g.@: @samp{"o} for o-umlaut. Load the library
+@file{iso-ascii} to do this.
-If your terminal can display Latin-1, you can display characters from
-other European character sets using a mixture of equivalent Latin-1
-characters and @sc{ascii} mnemonics. Use the Custom option
-@code{latin1-display} to enable this. The mnemonic @sc{ascii} sequences
-mostly correspond to those of the prefix input methods.
+ If your terminal can display Latin-1, you can display characters
+from other European character sets using a mixture of equivalent
+Latin-1 characters and @sc{ascii} mnemonics. Use the Custom option
+@code{latin1-display} to enable this. The mnemonic @sc{ascii}
+sequences mostly correspond to those of the prefix input methods.
@node Single-Byte Character Support
@section Single-byte Character Set Support
@findex set-keyboard-coding-system
@vindex keyboard-coding-system
If your keyboard can generate character codes 128 and up, representing
-non-ASCII characters, use the command @code{M-x
-set-keyboard-coding-system} or the Custom option
-@code{keyboard-coding-system} to specify this in the same way as for
-multibyte usage (@pxref{Specify Coding}).
-
-It is not necessary to do this under a window system which can
-distinguish 8-bit characters and Meta keys. If you do this on a normal
-terminal, you will probably need to use @kbd{ESC} to type Meta
-characters.@footnote{In some cases, such as the Linux console and
-@code{xterm}, you can arrange for Meta to be converted to @kbd{ESC} and
-still be able type 8-bit characters present directly on the keyboard or
-using @kbd{Compose} or @kbd{AltGr} keys.} @xref{User Input}.
+non-ASCII you can type those character codes directly.
+
+On a windowing terminal, you should not need to do anything special to
+use these keys; they should simply work. On a text-only terminal, you
+should use the command @code{M-x set-keyboard-coding-system} or the
+Custom option @code{keyboard-coding-system} to specify which coding
+system your keyboard uses (@pxref{Specify Coding}). Enabling this
+feature will probably require you to use @kbd{ESC} to type Meta
+characters; however, on a Linux console or in @code{xterm}, you can
+arrange for Meta to be converted to @kbd{ESC} and still be able type
+8-bit characters present directly on the keyboard or using
+@kbd{Compose} or @kbd{AltGr} keys. @xref{User Input}.
@item
You can use an input method for the selected language environment.
library is loaded, the @key{ALT} modifier key, if you have one, serves
the same purpose as @kbd{C-x 8}; use @key{ALT} together with an accent
character to modify the following letter. In addition, if you have keys
-for the Latin-1 ``dead accent characters'', they too are defined to
+for the Latin-1 ``dead accent characters,'' they too are defined to
compose with the following character, once @code{iso-transl} is loaded.
Use @kbd{C-x 8 C-h} to list the available translations as mnemonic
command names.
@cindex ISO Accents mode
@findex iso-accents-mode
@cindex Latin-1, Latin-2 and Latin-3 input mode
-For Latin-1, Latin-2 and Latin-3, @kbd{M-x iso-accents-mode} installs a
-minor mode which provides a facility like the @code{latin-1-prefix}
-input method but independent of the Leim package. This mode is
-buffer-local. It can be customized for various languages with @kbd{M-x
-iso-accents-customize}.
+For Latin-1, Latin-2 and Latin-3, @kbd{M-x iso-accents-mode} installs
+a minor mode which works much like the @code{latin-1-prefix} input
+method does not depend on having the input methods installed. This
+mode is buffer-local. It can be customized for various languages with
+@kbd{M-x iso-accents-customize}.
@end itemize
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