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date Mon, 13 Aug 2007 11:28:15 +0200
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1 This directory contains the source files for the C component of XEmacs.
2 Nothing in this directory is needed for using XEmacs once it is built
3 and installed, if the dumped Emacs is copied elsewhere.
4
5 See the files ../README and then ../INSTALL for installation instructions.
6
7 Under Unix, the file `Makefile.in.in' is used as a template by the script
8 `../configure' to produce `Makefile.in'. The same script then uses `cpp'
9 to produce the machine-dependent `Makefile' from `Makefile.in';
10 `Makefile' is the file which actually controls the compilation of
11 Emacs. Most of this should work transparently to the user; you should
12 only need to run `../configure', and then type `make'.
13
14 General changes for XEmacs:
15 ---------------------------
16 1. Lisp objects.
17
18 -- XFASTINT has been eliminated. Use of this expression as an lvalue
19 is incompatible with the union form of Lisp objects, and use as
20 an rvalue is likely to lead to errors and doesn't really save much
21 time. Expressions of the form `XFASTINT (obj) = num;' get replaced
22 by `obj = make_int (num);' or `XSETINT (obj, num);' and
23 expressions of the form `num = XFASTINT (obj);' get replaced by
24 `num = XINT (obj);'. Use Qzero in place of `make_int (0)'.
25
26 -- Use of XTYPE gets replaced by the appropriate predicate. Using
27 XTYPE only works for the small number of types that are not stored
28 using the Lisp_Record type (int, cons, string, and vector). For
29 example, `(XTYPE (foo) == Lisp_Buffer)' gets replaced by
30 `(BUFFERP (foo))'.
31
32 -- `XSET (obj, Lisp_Int, num)' gets replaced by `XSETINT (obj, num)',
33 for consistency.
34
35 -- Some occurrences of XSET need to get replaced by XSETR --
36 specifically, those where the type is not a primitive type
37 (primitive types are int, cons, string, and vector).
38
39 -- References to `XSTRING (obj)->size' get replaced with
40 `XSTRING_LENGTH (obj)'. This is currently for cosmetic reasons
41 but there may be other reasons in the future. (This change is
42 currently incomplete in the source files.)
43
44
45 2. Storage classes:
46
47 -- All occurrences of `const' should get replaced by CONST. This
48 is to work around a header conflict with X11R4.
49
50 -- All occurrences of `register' should be replaced by `REGISTER'.
51 It interferes with backtraces so we disable it if DEBUG_XEMACS
52 is defined.
53
54
55 3. Errors, messages, I18N3 snarfing:
56
57 -- Errors are continuable in XEmacs but are not in FSF Emacs.
58 Therefore, it's important that functions do something reasonable
59 if an error gets continued. If you want to signal a non-
60 continuable error, the call to Fsignal() gets put inside a
61 `while (1)' loop. To facilitate this, and also for proper I18N3
62 message snarfing, most calls to Fsignal() have been replaced by
63 calls to signal_error(), signal_simple_error(), etc. Look at
64 eval.c for a classification of various error functions.
65
66 -- Constant strings occurring in source files need to get wrapped
67 in a call to GETTEXT (or if inside of a call to `build_string',
68 change that function to `build_translated_string') if they don't
69 occur in certain places where the I18N3 message snarfer will see
70 them. For a complete discussion of this, see the file
71 lib-src/make-msgfile.lex.
72
73 NOTE: I18N3 support is not currently working, so the above may
74 or may not apply. Thus it is not a good idea to add random
75 GETTEXTs, unless you really know what you are doing.
76
77 -- Calls to `fprintf (stderr, ...)' and `printf (...)' get replaced
78 with calls to `stderr_out' and `stdout_out'. This is for I18N3
79 message snarfing.
80
81 4. Initialization:
82
83 -- FSF constructs like `obj = intern ("string"); staticpro (&obj);'
84 get replaced by `defsymbol (&obj);'. This is for code cleanness
85 and better purespace usage.
86 -- FSF constructs like
87 obj = intern ("error");
88 Fput (obj, Qerror_message, "message");
89 Fput (obj, Qerror_conditions, some list);
90 get replaced by calls to deferror(). See the definition of
91 deferror() for how the correct arguments to pass. This is for
92 code cleanness and I18N3 message snarfing.
93 -- Code in keys_of_foo() functions has been moved into Lisp.