xstr(1) 						      General Commands Manual							   xstr(1)

NAME

       xstr - extract strings from C programs to implement shared strings

SYNOPSIS

       [file]

DESCRIPTION

       maintains  a  file 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:

       extracts the strings from the C source in name, replacing string references with expressions of the form for some number.   An  appropriate
       declaration  of	is placed at the beginning of the file.  The resulting C text is placed in the file for subsequent compiling.  The strings
       from this file are placed in the 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 declaring the common space, can be created by the command:

       This  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.

       can also be used on a single file.  A command:

       creates files and as before, without using or affecting any file in the same directory.

       It may be useful to run after the C preprocessor if any macro definitions yield strings or if there is conditional code containing  strings
       that  are  not,	in  fact,  needed.  reads from its standard input when the argument is given.  An appropriate command sequence for running
       after the C preprocessor is:

       does not touch the file unless new items are added, thus can avoid remaking 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 both strings are  placed  in  the  data
       base, when placing only the longer one there would be sufficient.

AUTHOR

       was developed by the University of California, Berkeley.

FILES

       Data base of strings
       Massaged C source
       C source for definition of array
       Temp file when `xstr name' does not touch

SEE ALSO

       mkstr(1).

																	   xstr(1)