XSTR(1) BSD 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 expres-
sions of the form (&xstr[number]) for some number. An ap-
propriate declaration of xstr is prepended to the file. The
resulting C text is placed in the file x.c, to then be com-
piled. 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 defin-
itions yield strings or if there is conditional code which contains
strings which may not, in fact, be needed. An appropriate command se-
quence 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 short-
er string is seen first by xstr both strings will be placed in the data-
base, when just placing the longer one there will do.
MirOS BSD #10-current December 30, 1993 1
