XSTR(1) OpenBSD Reference Manual XSTR(1)NAMExstr - extract strings from C programs to implement shared strings
SYNOPSISxstr [-cv] [-l array] [-] [file ...]
DESCRIPTIONxstr 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, most
useful if they are also read-only.
The options are as follows:
- Cause xstr to read from the standard input.
-cxstr will extract the strings from the C source file or the
standard input (-), 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 database if they are not there already. Repeated
strings and strings which are suffixes of existing strings do
not cause changes to the database.
-l array Specify the named array in program references to abstracted
strings. The default array name is ``xstr''.
-v Be verbose.
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
The file xs.c 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. The following command creates
files x.c and xs.c as before, without using or affecting any strings file
in the same directory:
$ xstr name
It may be useful to run xstr after the C preprocessor if any macro
definitions yield strings or if there is conditional code which contains
strings which may not, in fact, be needed. 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, so that
make(1) can avoid remaking xs.o unless truly necessary.
FILES
strings database of strings
x.c massaged C source
xs.c C source for definition of array ``xstr''
/tmp/xs* temporary file when ``xstr name'' doesn't touch strings
SEE ALSOmkstr(1)HISTORY
The xstr command appeared in 3.0BSD.
BUGS
If a string is a suffix of another string in the database, but the
shorter string is seen first by xstr both strings will be placed in the
database, when just placing the longer one there will do.
OpenBSD 4.9 August 16, 2009 OpenBSD 4.9
