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[metaconfig.git] / README_U
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1Line Description
2======= =======================================================================
3
9a94a89a 4?MAKE: The ?MAKE: line records dependencies
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9a94a89a 6 ?MAKE:symbol list: dependency list [+optional]
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7
8 This is the first dependency line. The first "symbol list"
9 should list all the symbols built by this unit (i.e. whose
10 value is computed by the shell section of the unit). Symbols
11 should be space separated. If a defined symbol is for internal
12 use only and should not appear in the generated "config.sh"
13 file, then it should be preceded by a '+' (not to be confused
14 with optional dependencies defined hereafter).
15 The second part of the list (after the middle ':') is the unit
16 dependency. It should list all the needed special units, as
17 well as all the symbols used by the shell implementation. If
18 a symbol is nedded but its configuration value is not critical,
19 it can be preceded by a '+', in which case it is called a
20 conditional dependency: its corresponding unit will be loaded
21 if, and only if, that symbol is otherwise really wanted;
22 otherwise the default value will be used.
23
9a94a89a 24 ?MAKE: <tab> command
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25
26 There can be one or more command lines following the initial
27 dependency lines. Those commands will be executed when the
28 unit is wanted to load them into "Configure".
29 Note that the leading <tab> character is required before the
30 "command".
31
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32?INIT: Initializations printed verbatim
33
34?LINT: Hints for metalint
35
36 set Listed variables are set
37 ?LINT:set d_getservprotos
38 describe Listed shell variables are described
39 ?LINT:describe awk ar bash bison byacc cat chgrp chmod chown
40 create Listed created files in regular units
41 ?LINT:create mips
42 known Listed C variables are described
43 ?LINT:known StGiFy
44 change Shell variable ok to be changed
45 ?LINT:change CONFIG_H
46 extern Variables known to be externally defined
47 ?LINT:extern CONFIG_H
48 usefile Files marked as being used
49 ?LINT:usefile foobar
50 use Variables declared as used by unit
51 ?LINT:use PERL_CONFIG_SH
52 define Listed variables are defined
53 ?LINT:define fieldn
54 empty Empty unit file
55 ?LINT:empty
56 unclosed Unclosed here-documents
57 ?LINT:unclosed EOT
58 nothere Not a here-document name
59 nocomment OK if leading unit ': comment' missing
60 ?LINT:nocomment
61
62?RCS: RCS comments are ignored
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9a94a89a 64 To be used for RCS comments, at the top of the unit.
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9a94a89a 66?C: C symbols
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68 Comments for #defines
69
70?D: Default value for conditional symbols
71
72 ?D:osname=''
73
74?E: Example of usage
75
76?F: Produced files
77
78 Defines what files are created by this module
79
80 Files produced in the UU directory and which are identified by the
81 convention ./filename. Files !filename are not produced, i.e. they are
82 temporary or externally provided.
83
84 ?F:cppstdin !testcpp.out !testcpp.c
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86?H: Process the config.h lines
87
88 Defines the part to be included in the generated config_h.SH
89
90 To get #ifdefs in config_h.SH, you'll need strange constructs like
91
92 ?H:?%<:@if USE_SITECUSTOMIZE
93 ?H:?%<:#ifndef USE_SITECUSTOMIZE
94 ?H:?%<:#$usesitecustomize USE_SITECUSTOMIZE /**/
95 ?H:?%<:#endif
96 ?H:?%<:@end
97
98?I: Added includes
99
100?L: Added libraries
101
102?M: Process the confmagic.h lines
103
104?O: Unit obsolescence
105
106?P: Location of PD implementation file
107
108?S: Shell variables
109
110 ?S:symbol_name (obsolete symbol list)]:
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111
112 Introduces a shell symbol. This first line names the symbol,
113 optionally followed by a list enclosed between parenthesis and
114 giving the obsolete equivalent. Those obsolete symbols will be
115 remapped to the new "symbol_name" if the -o option is given to
116 "metaconfig".
117
9a94a89a 118 ?S: <tab> any text, for "Porting/Glossary"
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119
120 Basically a comment describing the shell symbol, which will be
121 extracted by "makegloss" into the Glossary file.
122
9a94a89a 123 ?S:.
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124
125 Closes the shell symbol comment.
126
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127?T: Shell temporaries used
128
129 What variables are used as temporary variables
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9a94a89a 131?V: Visible symbols like 'rp', 'dflt'
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132
133 ?V:fieldn
134
9a94a89a 135?W: Wanted value for interpreter
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9a94a89a 137?X: User comment is ignored
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138
139 General purpose comments. May appear anywhere in the unit but must be
140 left justfied. For RCS comments, please use the ?RCS: comment form.
141
9a94a89a 142?Y: User-defined layout preference
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143
144 Declare a layout directive for this unit. That directive may be one
145 of the strings "top", "default" or "bottom" (case does not matter,
146 recommended style is to spell them out uppercased). If omitted,
147 "default" is assumed.
148
149 This directive is only required if you wish to force a unit at the
150 top or the bottom of the generated "Configure" script, as unit
151 dependencies permit it. Important questions may thus be forced
152 at the beginning. Within the same layout class, units are sorted
153 alphabetically with two special cases for d_* and i_* units, forced
154 respectively at the top and bottom of their classes (but these
155 should belong to the default class).
156
157 It you force at the top a unit whose dependencies require all the
158 other unit to precede it, you achieve nothing interesting. Therefore,
159 that directive should really be used to increase the priority of
160 some interactive units that do not depend on many other user-visible
161 symbols, like path-related questions.
162
163 ?Y:TOP
164
165lines can be made conditional (see Config_sh.U)
166
167@if d_portable
168:
169:
170@end