xstr(1)
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xstr Command
extract strings from C programs to implement shared strings in
DG/UX
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SYNTAX
xstr [ -c ] [ - ] [ file ]
DESCRIPTION
Xstr maintains a file strings into which strings in component
parts of a large program are hashed. These strings are replaced
with references to this common area. This serves to implement
shared constant strings, which are most useful if they are also
read-only.
The command
xstr -c name
will extract the strings from the C source in name, replacing
string references by expressions of the form (&xstr[number]) for
some number. An appropriate declaration of xstr is prepended to
the file. The resulting C text is placed in the file x.c, to
then be compiled. The strings from this file are placed in the
strings data base if they are not there already. Repeated
strings and strings which are suffixes of existing strings do not
cause changes to the data base.
After all components of a large program have been compiled, a
file xs.c declaring the common xstr space can be created by a
command of the form
xstr
This xs.c file should then be compiled and loaded with the rest
of the program. If possible, the array can be made read-only
(shared), saving space and swap overhead.
Xstr can also be used on a single file. A command
xstr name
creates files x.c and xs.c as before, without using or affecting
any strings file in the same directory.
It may be useful to run xstr after the C preprocessor if any
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xstr(1)
macro definitions yield strings or if there is conditional code
which contains strings which may not, in fact, be needed. Xstr
reads from its standard input when the argument `-' is given. An
appropriate command sequence for running xstr after the C
preprocessor is:
cc -E name.c | xstr -c -
cc -c x.c
mv x.o name.o
Xstr does not touch the file strings unless new items are added,
thus make can avoid remaking xs.o unless truly necessary.
FILES
strings Data base of strings
x.c Massaged C source
xs.c C source for definition of array `xstr'
/tmp/xs* Temp file when `xstr name' doesn't touch strings
SEE ALSO
mkstr(1)
BUGS
If a string is a suffix of another string in the data base, but
the shorter string is seen first by xstr both strings will be
placed in the data base, when just placing the longer one there
will do.
DG/UX 4.00 Page 2
Licensed material--property of copyright holder(s)