view modules/sample/internal/sample.c @ 2417:8b907450718f

[xemacs-hg @ 2004-12-05 08:48:12 by ben] The section on Troubleshooting (now 2.3) has been completely written and includes a lot of stuff that is not properly documented anywhere else. A fair amount of obsolete info has been deleted and I've incorporated the comments that people (mostly Stephen T) made. Former chapter 3 has been split up in two, one pertaining to basic I/O and the other to external I/O. What were formerly chapters 5 and 6 no longer exist as such; the info in them has been distributed across various other chapters. Old chapter 4 got split up, part going to the new chapter 4 on external I/O and part going to the new chapter 5 on the Internet. In this new chapter, stuff not pertaining to a specific package (e.g. VM or GNUS) was taken out of package-specific sections and a general mail section was constituted. Part of old chapter 5 remains in a new chapter 6 devoted to Emacs Lisp and other advanced stuff, and a section from old chapter 3 on basic init-file Lisp and some stuff from old chapter 5 on Info. The rest of chapter 5 was just misc and has gotten scattered to the winds (mostly in chapters 3 and 4). Old chapter 6 has also gotten quite scattered; there is no longer any section specifically devoted to Windows except one of the Installation sections (along with a section specfically devoted to Unix), and the rest has moved to join the appropriate non-Windows-specific section elsewhere. A lot of chapters had their sections rearranged and likewise for sections having entries rearranged, with the intention that the new arrangement should be more natural. In general I hope that stuff should be much easier to locate. I also rewrote the entries on the relation between XEmacs and GNU Emacs on the authors of XEmacs, including lots of info on who wrote specific subsections. However, this history is certainly not complete; I hope people will look over this and fix it up as necessary.
author ben
date Sun, 05 Dec 2004 08:48:12 +0000
parents 25e260cb7994
children dce479915b74
line wrap: on
line source

/*
 * Very simple sample module. Illustrates most of the salient features
 * of Emacs dynamic modules.
 * (C) Copyright 1998, 1999 J. Kean Johnston. All rights reserved.
 * (C) Copyright 2002 Jerry James.
 */

#include <config.h>
#include "lisp.h"

/*
 * This sample introduces three new Lisp objects to the Lisp reader.
 * The first, a simple boolean value, and the second a string. The
 * Third is a sample function that simply prints a message.
 */
int sample_bool;
Lisp_Object Vsample_string;

DEFUN ("sample-function", Fsample_function, 0, 0, "", /*
This is a sample function loaded dynamically.

You will notice in the source code for this module that the
declaration is identical to internal Emacs functions.  This
makes it possible to use the exact same code in a dumped
version of Emacs.
*/
        ())
{
  message ("Eureka! It worked");
  return Qt;
}

/*
 * Each dynamically loaded Emacs module is given a name at compile
 * time. This is a short name, and must be a valid part of a C
 * identifier.  This name is used to construct the name of several
 * functions which must appear in the module source code.
 * The first such function, modules_of_XXXX, should load in any dependent
 * modules. This function is optional, and the module will still load if
 * it is not present in the module.
 *
 * The second function, which is NOT optional, is syms_of_XXXX, in which
 * all functions that the module will be provided are declared. This
 * function will contain calls to DEFSUBR().
 *
 * The third function, which is also NOT optional, is vars_of_XXXX, in
 * which you declare all variables that the module provides. This
 * function will contain calls to DEFVAR_LISP(), DEFVAR_BOOL() etc.
 *
 * When declaring functions and variables in the syms_of_XXXX and
 * vars_of_XXXX functions, you use the exact same syntax that you
 * would as if this module were being compiled into the pure Emacs.
 *
 * The fourth function, which is optional, is unload_XXXX, in which actions
 * that must be taken to unload the module are listed.  XEmacs will unbind
 * functions and variables for you.  Anything else that must be done should
 * appear in this function.
 *
 * All four of these functions are declared as void functions,
 * taking no parameters. Since this sample module is called 'sample',
 * the functions will be named 'modules_of_sample', 'syms_of_sample',
 * 'vars_of_sample', and 'unload_sample'.
 */

void
modules_of_sample()
{
  /*
   * This function isn't actually required as we will not be loading
   * in any dependent modules, but if we were, we would do something like:
   * emodules_load ("dependent.ell", "sample2", "1.0.0");
   */
}

void
syms_of_sample()
{
  DEFSUBR(Fsample_function);
}

void
vars_of_sample()
{
  DEFVAR_LISP ("sample-string", &Vsample_string /*
This is a sample string, declared in a dynamic module.

The syntax and conventions used for all normal Emacs variables
apply equally to modules, using an identical syntax.
*/ );

  DEFVAR_BOOL ("sample-boolean", &sample_bool /*
*Sample boolean value, in a dynamic module.

This is a user-settable variable, as indicated by the *
as the first character of the description. Declared in
a module exactly as it would be internally in Emacs.
*/ );
}

#ifdef HAVE_SHLIB
void
unload_sample()
{
  /* We don't need to do anything here in the sample case.  However, if you
     create any new types with INIT_LRECORD_IMPLEMENTATION (sample_type), then
     UNDEF_LRECORD_IMPLEMENTATION (sample_type) must appear here.  Also, any
     symbols declared with DEFSYMBOL (Qsample_var), or one of its variants,
     must have a corresponding unstaticpro_nodump (&Qsample_var) here. */
}
#endif