1 .\" Copyright (c) 1980, 1993
2 .\" The Regents of the University of California. All rights reserved.
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5 .\" modification, are permitted provided that the following conditions
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32 .\" @(#)xstr.1 8.2 (Berkeley) 12/30/93
40 .Nd "extract strings from C programs to implement shared strings"
49 utility maintains a file
51 into which strings in component parts of a large program are hashed.
52 These strings are replaced with references to this common area.
53 This serves to implement shared constant strings, most useful if they
56 The following options are available:
57 .Bl -tag -width indent
59 Read from the standard input.
61 Extract the strings from the C source
66 string references by expressions of the form
70 An appropriate declaration of
72 is prepended to the file.
73 The resulting C text is placed in the file
76 The strings from this file are placed in the
78 data base if they are not there already.
79 Repeated strings and strings which are suffixes of existing strings
80 do not cause changes to the data base.
85 After all components of a large program have been compiled a file
89 space can be created by a command of the form
95 should then be compiled and loaded with the rest
97 If possible, the array can be made read-only (shared) saving
98 space and swap overhead.
102 utility can also be used on a single file.
104 .Bd -literal -offset indent
112 as before, without using or affecting any
114 file in the same directory.
116 It may be useful to run
118 after the C preprocessor if any macro definitions yield strings
119 or if there is conditional code which contains strings
120 which may not, in fact, be needed.
121 An appropriate command sequence for running
123 after the C preprocessor is:
125 .Bd -literal -offset indent -compact
126 cc -E name.c | xstr -c -
133 utility does not touch the file
135 unless new items are added, thus
139 unless truly necessary.
141 .Bl -tag -width ".Pa /tmp/xs*" -compact
147 C source for definition of array
163 If a string is a suffix of another string in the data base,
164 but the shorter string is seen first by
166 both strings will be placed in the data base, when just
167 placing the longer one there will do.