OpenSolaris 2009.06 - man page for xstr (opensolaris section 1)

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xstr(1) 				  User Commands 				  xstr(1)

NAME
       xstr - extract strings from C programs to implement shared strings

SYNOPSIS
       xstr -c filename [-v] [-l array]

       xstr [-l array]

       xstr filename [-v] [-l array]

DESCRIPTION
       xstr maintains a file called strings into which strings in component parts of a large pro-
       gram 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:

	 example% xstr -c filename

       extracts 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 declaring the common
       xstr space called xs.c can be created by a command of the form:

	 example% xstr

       This xs.c file should then be compiled and loaded with the rest of the program.	If possi-
       ble, the array can be made read-only (shared) saving space and swap overhead.

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

       example% xstr filename

       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 which contains strings which may not, in fact, be
       needed. xstr reads from the standard input when the argument `-' is given. An  appropriate
       command sequence for running xstr after the C preprocessor is:

	 example% cc -E name.c | xstr -c -
	 example% cc -c x.c
	 example% mv x.o name.o

       xstr  does  not touch the file strings unless new items are added; thus make(1S) can avoid
       remaking xs.o unless truly necessary.

OPTIONS
       -c filename	 Take C source text from filename.

       -v		 Verbose: display a progress report indicating	where  new  or	duplicate
			 strings were found.

       -l array 	 Specify  the  named   array in program references to abstracted strings.
			 The default array name is xstr.

FILES
       strings	   data base of strings

       x.c	   massaged C source

       xs.c	   C source for definition of array "xstr*(rq

       /tmp/xs*    temp file when xstr filename doesn't touch strings

ATTRIBUTES
       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWcsu			   |
       +-----------------------------+-----------------------------+

SEE ALSO
       make(1S), attributes(5)

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 would do.

NOTES
       Be aware that xstr indiscriminately replaces all strings  with  expressions  of	the  form
       &xstr[number]  regardless  of the way the original C code might have used the string.  For
       example, you will encounter a problem with  code  that  uses  sizeof()  to  determine  the
       length  of  a  literal  string because xstr will replace the literal string with a pointer
       that most likely will have a different size than the string's. To circumvent this problem:

	   o	  use strlen() instead of  sizeof(); note that	sizeof() returns the size of  the
		  array  (including the null byte at the end), whereas strlen() doesn't count the
		  null byte. The equivalent of sizeof("xxx") really is (strlen("xxx"))+1.

	   o	  use #define for operands of sizeof() and use the define'd version. xstr ignores
		  #define  statements.	 Make  sure you run xstr on filename before you run it on
		  the preprocessor.

       You will also encounter a problem when declaring an initialized	character  array  of  the
       form

	 char x[] = "xxx";

       xstr  will  replace   xxx with an expression of the form &xstr[number] which will not com-
       pile.  To circumvent this problem, use static char *x = "xxx" instead of static char x[] =
       "xxx".

SunOS 5.11				   14 Sep 1992					  xstr(1)
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