Generating the .defs files.
| Appendix H. Wrapping C Libraries with gmmproc |

## Generating the .defs files.

The .defs file are text files, in a lisp format, that describe the API of a C library, including its

- objects (GObjects, widgets, interfaces, boxed-types and plain structs)

- functions

- enums

- signals

- properties

- vfuncs

At the moment, we have separate tools for generating different parts of these .defs, so we split them up into separate files. For instance, in `gtkmm/gtk/src`, you will find these files:

`gtk.defs`

  Includes the other files.

`gtk_methods.defs`

  Objects and functions.

`gtk_enums.defs`

  Enums.

`gtk_signals.def`

  Signals and properties.

`gtk_vfuncs.defs`

  vfuncs (function pointer member fields in structs), written by hand.

### Generating the methods .defs

This .defs file describes objects and their functions. It is generated by the h2def.py script which you can find in pygtk's codegen directory. For instance,

    $ ./h2def.py /usr/include/gtk-2.0/gtk/*.h > gtk_methods.defs

### Generating the enums .defs

This .defs file describes enum types and their possible values. It is generated by the `enum.pl` script which you can find in glibmm's `tools` directory. For instance,

    $ ./enum.pl /usr/include/gtk-2.0/gtk/*.h > gtk_enums.defs

### Generating the signals and properties .defs

This .defs file describes signals and properties. It is generated by the special `extra_defs` utility that is in every wrapping project, such as `gtkmm/tools/extra_defs_gen/`. For instance

    $ cd tools/extra_defs_gen
    $ ./generate_extra_defs > gtk_signals.defs

You must edit the source code of your own `extra_defs_gen` tool in order to generate the .defs for the C types that you wish to wrap. Start by renaming the file:

    $ cd tools/extra_defs_gen
    $ mv generate_defs_gda.cc generate_defs_example.cc

Then edit the `Makefile.am` so that it mentions the new file name, and edit the new `.cc` file to specify the correct types. For instance, your `main()` function might look like this:

    #include <libsomething.h>

    int main (int argc, char *argv[])
    {
        libexample_init(argc, argv);

        std::cout << get_defs(EXAMPLE_TYPE_SOMETHING)
                  << get_defs(EXAMPLE_TYPE_THING);
        return 0;
    }

### Writing the vfuncs .defs

Appendix H. Wrapping C Libraries with gmmproc |  | The .hg and .ccg files