shtool-scpp


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.

       -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\n", 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)
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