HP-UX Reference (11i v2 07/12) - 1 User Commands N-Z (vol 2)

x
xstr(1) xstr(1)
NAME
xstr - extract strings from C programs to implement shared strings
SYNOPSIS
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
extracts the strings from the C source in name, replacing string references with expressions of the form
(&xstr[number]) for some number. An appropriate declaration of
xstr is placed at the beginning of
the file. The resulting C text is placed in the file
x.c, for subsequent compiling. The strings from this file
are placed in the
strings database if they are not there already. Repeated strings and strings that 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 the command:
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 macro definitions yield strings or if there is
conditional code containing strings that are not, in fact, needed. xstr reads from its standard input
when the argument - is given. An appropriate command sequence for running xstr after the C prepro-
cessor 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 (see make(1)).
WARNINGS
If a string is a suffix of another string in the data base, but the shorter string is seen first by
xstr, both
strings are placed in the data base, when placing only the longer one there would be sufficient.
AUTHOR
xstr was developed by the University of California, Berkeley.
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’ does not touch strings
SEE ALSO
mkstr(1).
444 Hewlett-Packard Company − 1 − HP-UX 11i Version 2: December 2007 Update