1 /* extensions.c - registering and loading extensions.
3 * Copyright (C) 2001 Free Software Foundation, Inc.
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2, or (at your option)
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this software; see the file COPYING. If not, write to
17 * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
18 * Boston, MA 02111-1307 USA
20 * As a special exception, the Free Software Foundation gives permission
21 * for additional uses of the text contained in its release of GUILE.
23 * The exception is that, if you link the GUILE library with other files
24 * to produce an executable, this does not by itself cause the
25 * resulting executable to be covered by the GNU General Public License.
26 * Your use of that executable is in no way restricted on account of
27 * linking the GUILE library code into it.
29 * This exception does not however invalidate any other reasons why
30 * the executable file might be covered by the GNU General Public License.
32 * This exception applies only to the code released by the
33 * Free Software Foundation under the name GUILE. If you copy
34 * code from other Free Software Foundation releases into a copy of
35 * GUILE, as the General Public License permits, the exception does
36 * not apply to the code that you add in this way. To avoid misleading
37 * anyone as to the status of such modified files, you must delete
38 * this exception notice from them.
40 * If you write modifications of your own for GUILE, it is your choice
41 * whether to permit this exception to apply to your modifications.
42 * If you do not wish that, delete this exception notice. */
46 #include "libguile/_scm.h"
47 #include "libguile/strings.h"
48 #include "libguile/gc.h"
49 #include "libguile/dynl.h"
51 #include "libguile/extensions.h"
53 typedef struct extension_t
55 struct extension_t
*next
;
62 static extension_t
*registered_extensions
;
64 /* Register a LIB/INIT pair for use by `scm_load_extension'. LIB is
65 allowed to be NULL and then only INIT is used to identify the
66 registered entry. This is useful when you don't know the library
67 name (which isn't really relevant anyway in a completely linked
68 program) and you are sure that INIT is unique (which it must be for
69 static linking). Hmm, given this reasoning, what use is LIB
74 scm_c_register_extension (const char *lib
, const char *init
,
75 void (*func
) (void *), void *data
)
77 extension_t
*ext
= scm_malloc (sizeof(extension_t
));
79 ext
->lib
= scm_strdup (lib
);
82 ext
->init
= scm_strdup (init
);
86 ext
->next
= registered_extensions
;
87 registered_extensions
= ext
;
91 load_extension (SCM lib
, SCM init
)
93 /* Search the registry. */
97 for (ext
= registered_extensions
; ext
; ext
= ext
->next
)
98 if ((ext
->lib
== NULL
|| !strcmp (ext
->lib
, SCM_STRING_CHARS (lib
)))
99 && !strcmp (ext
->init
, SCM_STRING_CHARS (init
)))
101 ext
->func (ext
->data
);
106 /* Dynamically link the library. */
108 scm_dynamic_call (init
, scm_dynamic_link (lib
));
112 scm_c_load_extension (const char *lib
, const char *init
)
114 load_extension (scm_makfrom0str (lib
), scm_makfrom0str (init
));
117 SCM_DEFINE (scm_load_extension
, "load-extension", 2, 0, 0,
119 "Load and initialize the extension designated by LIB and INIT.\n"
120 "When there is no pre-registered function for LIB/INIT, this is\n"
124 "(dynamic-call INIT (dynamic-link LIB))\n"
127 "When there is a pre-registered function, that function is called\n"
130 "Normally, there is no pre-registered function. This option exists\n"
131 "only for situations where dynamic linking is unavailable or unwanted.\n"
132 "In that case, you would statically link your program with the desired\n"
133 "library, and register its init function right after Guile has been\n"
136 "LIB should be a string denoting a shared library without any file type\n"
137 "suffix such as \".so\". The suffix is provided automatically. It\n"
138 "should also not contain any directory components. Libraries that\n"
139 "implement Guile Extensions should be put into the normal locations for\n"
140 "shared libraries. We recommend to use the naming convention\n"
141 "libguile-bla-blum for a extension related to a module `(bla blum)'.\n"
143 "The normal way for a extension to be used is to write a small Scheme\n"
144 "file that defines a module, and to load the extension into this\n"
145 "module. When the module is auto-loaded, the extension is loaded as\n"
146 "well. For example,\n"
149 "(define-module (bla blum))\n"
151 "(load-extension \"libguile-bla-blum\" \"bla_init_blum\")\n"
153 #define FUNC_NAME s_scm_load_extension
155 SCM_VALIDATE_STRING (1, lib
);
156 SCM_VALIDATE_STRING (2, init
);
157 load_extension (lib
, init
);
158 return SCM_UNSPECIFIED
;
163 scm_init_extensions ()
165 registered_extensions
= NULL
;
166 #include "libguile/extensions.x"