SHTOOL-SCPP.TMP(1)					      GNU Portable Shell Tool						SHTOOL-SCPP.TMP(1)

NAME

       shtool-scpp - GNU shtool C source file pre-processor

SYNOPSIS

       shtool scpp [-v|--verbose] [-p|--preserve] [-f|--filter filter] [-o|--output ofile] [-t|--template tfile] [-M|--mark mark] [-D|--define
       dname] [-C|--class cname] file [file ...]

DESCRIPTION

       This command is an additional ANSI C source file pre-processor for sharing cpp(1) code segments, internal variables and internal functions.
       The intention for this comes from writing libraries in ANSI C. Here a common shared internal header file is usually used for sharing
       information between the library source files.

       The operation is to parse special constructs in files, generate a few things out of these constructs and insert them at position mark in
       tfile by writing the output to ofile. Additionally the files are never touched or modified. Instead the constructs are removed later by the
       cpp(1) phase of the build process. The only prerequisite is that every file has a ``"#include ""ofile"""'' at the top.

       This command provides the following features: First it avoids namespace pollution and reduces prototyping efforts for internal symbols by
       recognizing functions and variables which are defined with the storage class identifier ``cname''.  For instance if cname is ``intern'', a
       function ``"intern void *foobar(int quux)"'' in one of the files is translated into both a ``"#define foobar __foobar"'' and a ``"extern
       void *foobar(int quux);"'' in ofile. Additionally a global ``"#define" cname "/**/"'' is also created in ofile to let the compiler silently
       ignore this additional storage class identifier.

       Second, the library source files usually want to share "typedef"s, "#define"s, etc.  over the source file boundaries. To achieve this one
       can either place this stuff manually into tfile or use the second feature of scpp: All code in files encapsulated with ``"#if "dname ...
       "#endif"'' is automatically copied to ofile. Additionally a global ``"#define" dname 0'' is also created in ofile to let the compiler
       silently skip this parts (because it was already found in the header).

OPTIONS

       The following command line options are available.

       -v, --verbose
	   Display some processing information.

       -p, --preserve
	   Preserves ofile independent of the generated ``#line'' lines. This is useful for Makefiles if the real contents of ofile will not
	   change, just line numbers. Default is to overwrite.

       -f, --filter filter
	   Apply one or more pre-processing sed(1) filter commands (usually of type ``"s/.../.../"'') to each input file before their input is
	   parsed.  This option can occur multiple times.

       -o, --output ofile
	   Output file name. Default is "lib.h".

       -t, --template tfile
	   Template file name. Default is "lib.h.in".

       -M, --mark mark
	   Mark to be replaced by generated constructs. Default is "%%MARK%%".

       -D, --define dname
	   FIXME. Default is "cpp".

       -C, --class cname
	   FIXME. Default is "intern".

EXAMPLE

	#   Makefile
	SRCS=foo_bar.c foo_quux.c
	foo_p.h: foo_p.h.in
	     shtool scpp -o foo_p.h -t foo_p.h.in 
			 -M %%MARK%% -D cpp -C intern $(SRCS)

	/* foo_p.h.in */
	#ifndef FOO_P_H
	#define FOO_P_H
	%%MARK%%
	#endif /* FOO_P_H */

	/* foo_bar.c */
	#include "foo_p.h"
	#if cpp
	#define OURS_INIT 4711
	#endif
	intern int ours;
	static int myone = 0815;
	intern int bar(void)
	{
	    ours += myone;
	}

	/* foo_quux.c */
	#include "foo_p.h"
	int main(int argc, char *argv[])
	{
	    int i;
	    ours = OURS_INIT
	    for (i = 0; i < 10; i++) {
		bar();
		printf("ours now %d
", ours);
	    }
	    return 0;
	}

HISTORY

       The GNU shtool scpp command was originally written by Ralf S.  Engelschall <rse@engelschall.com> in 1999 for GNU shtool.  Its was prompted
       by the need to have a pre-processing facility in the GNU pth project.

SEE ALSO

       shtool(1), cpp(1).

18-Jul-2008							   shtool 2.0.8 						SHTOOL-SCPP.TMP(1)