Each terminal type can have a Lisp library to be loaded into Emacs when it is run on that type of terminal. For a terminal type named
termtype, the library is called
term/termtype. (If there is an entry of the form
(termtype . alias) in the
term-file-aliases association list, Emacs uses
alias in place of
termtype.) The library is found by searching the directories
load-path as usual and trying the suffixes ‘
.elc’ and ‘
.el’. Normally it appears in the subdirectory
term of the directory where most Emacs libraries are kept.
The usual purpose of the terminal-specific library is to map the escape sequences used by the terminal’s function keys onto more meaningful names, using
input-decode-map. See the file
term/lk201.el for an example of how this is done. Many function keys are mapped automatically according to the information in the Termcap data base; the terminal-specific library needs to map only the function keys that Termcap does not specify.
When the terminal type contains a hyphen, only the part of the name before the first hyphen is significant in choosing the library name. Thus, terminal types ‘
aaa-48’ and ‘
aaa-30-rv’ both use the library
term/aaa. The code in the library can use
(getenv "TERM") to find the full terminal type name.
The library’s name is constructed by concatenating the value of the variable
term-file-prefix and the terminal type. Your
.emacs file can prevent the loading of the terminal-specific library by setting
Emacs runs the hook
tty-setup-hook at the end of initialization, after both your
.emacs file and any terminal-specific library have been read in. Add hook functions to this hook if you wish to override part of any of the terminal-specific libraries and to define initializations for terminals that do not have a library. See Hooks.