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e2ab7927 MV |
1 | /* extensions.c - registering and loading extensions. |
2 | * | |
3 | * Copyright (C) 2001 Free Software Foundation, Inc. | |
4 | * | |
73be1d9e MV |
5 | * This library is free software; you can redistribute it and/or |
6 | * modify it under the terms of the GNU Lesser General Public | |
7 | * License as published by the Free Software Foundation; either | |
8 | * version 2.1 of the License, or (at your option) any later version. | |
e2ab7927 | 9 | * |
73be1d9e MV |
10 | * This library 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 GNU | |
13 | * Lesser General Public License for more details. | |
e2ab7927 | 14 | * |
73be1d9e MV |
15 | * You should have received a copy of the GNU Lesser General Public |
16 | * License along with this library; if not, write to the Free Software | |
17 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
18 | */ | |
e2ab7927 | 19 | |
c0fc1089 RB |
20 | #if HAVE_CONFIG_H |
21 | # include <config.h> | |
22 | #endif | |
23 | ||
fbbdb121 GH |
24 | #include <string.h> |
25 | ||
e2ab7927 MV |
26 | #include "libguile/_scm.h" |
27 | #include "libguile/strings.h" | |
28 | #include "libguile/gc.h" | |
29 | #include "libguile/dynl.h" | |
30 | ||
31 | #include "libguile/extensions.h" | |
32 | ||
1be6b49c ML |
33 | typedef struct extension_t |
34 | { | |
35 | struct extension_t *next; | |
e2ab7927 MV |
36 | const char *lib; |
37 | const char *init; | |
38 | void (*func)(void *); | |
39 | void *data; | |
1be6b49c | 40 | } extension_t; |
e2ab7927 | 41 | |
1be6b49c | 42 | static extension_t *registered_extensions; |
e2ab7927 | 43 | |
bef38a17 MV |
44 | /* Register a LIB/INIT pair for use by `scm_load_extension'. LIB is |
45 | allowed to be NULL and then only INIT is used to identify the | |
46 | registered entry. This is useful when you don't know the library | |
47 | name (which isn't really relevant anyway in a completely linked | |
48 | program) and you are sure that INIT is unique (which it must be for | |
49 | static linking). Hmm, given this reasoning, what use is LIB | |
50 | anyway? | |
51 | */ | |
52 | ||
e2ab7927 MV |
53 | void |
54 | scm_c_register_extension (const char *lib, const char *init, | |
55 | void (*func) (void *), void *data) | |
56 | { | |
4c9419ac | 57 | extension_t *ext = scm_malloc (sizeof(extension_t)); |
bef38a17 | 58 | if (lib) |
4c9419ac | 59 | ext->lib = scm_strdup (lib); |
bef38a17 MV |
60 | else |
61 | ext->lib = NULL; | |
4c9419ac | 62 | ext->init = scm_strdup (init); |
e2ab7927 MV |
63 | ext->func = func; |
64 | ext->data = data; | |
65 | ||
66 | ext->next = registered_extensions; | |
67 | registered_extensions = ext; | |
68 | } | |
69 | ||
70 | static void | |
71 | load_extension (SCM lib, SCM init) | |
72 | { | |
73 | /* Search the registry. */ | |
74 | { | |
1be6b49c | 75 | extension_t *ext; |
e2ab7927 MV |
76 | |
77 | for (ext = registered_extensions; ext; ext = ext->next) | |
bef38a17 | 78 | if ((ext->lib == NULL || !strcmp (ext->lib, SCM_STRING_CHARS (lib))) |
e2ab7927 MV |
79 | && !strcmp (ext->init, SCM_STRING_CHARS (init))) |
80 | { | |
81 | ext->func (ext->data); | |
82 | return; | |
83 | } | |
84 | } | |
85 | ||
86 | /* Dynamically link the library. */ | |
e2ab7927 MV |
87 | scm_dynamic_call (init, scm_dynamic_link (lib)); |
88 | } | |
89 | ||
90 | void | |
91 | scm_c_load_extension (const char *lib, const char *init) | |
92 | { | |
93 | load_extension (scm_makfrom0str (lib), scm_makfrom0str (init)); | |
94 | } | |
95 | ||
96 | SCM_DEFINE (scm_load_extension, "load-extension", 2, 0, 0, | |
97 | (SCM lib, SCM init), | |
72dd0a03 | 98 | "Load and initialize the extension designated by LIB and INIT.\n" |
9401323e NJ |
99 | "When there is no pre-registered function for LIB/INIT, this is\n" |
100 | "equivalent to\n" | |
101 | "\n" | |
102 | "@lisp\n" | |
103 | "(dynamic-call INIT (dynamic-link LIB))\n" | |
104 | "@end lisp\n" | |
105 | "\n" | |
106 | "When there is a pre-registered function, that function is called\n" | |
107 | "instead.\n" | |
108 | "\n" | |
109 | "Normally, there is no pre-registered function. This option exists\n" | |
110 | "only for situations where dynamic linking is unavailable or unwanted.\n" | |
111 | "In that case, you would statically link your program with the desired\n" | |
112 | "library, and register its init function right after Guile has been\n" | |
113 | "initialized.\n" | |
114 | "\n" | |
115 | "LIB should be a string denoting a shared library without any file type\n" | |
116 | "suffix such as \".so\". The suffix is provided automatically. It\n" | |
117 | "should also not contain any directory components. Libraries that\n" | |
118 | "implement Guile Extensions should be put into the normal locations for\n" | |
119 | "shared libraries. We recommend to use the naming convention\n" | |
120 | "libguile-bla-blum for a extension related to a module `(bla blum)'.\n" | |
121 | "\n" | |
122 | "The normal way for a extension to be used is to write a small Scheme\n" | |
123 | "file that defines a module, and to load the extension into this\n" | |
124 | "module. When the module is auto-loaded, the extension is loaded as\n" | |
125 | "well. For example,\n" | |
126 | "\n" | |
127 | "@lisp\n" | |
128 | "(define-module (bla blum))\n" | |
129 | "\n" | |
130 | "(load-extension \"libguile-bla-blum\" \"bla_init_blum\")\n" | |
131 | "@end lisp") | |
e2ab7927 MV |
132 | #define FUNC_NAME s_scm_load_extension |
133 | { | |
134 | SCM_VALIDATE_STRING (1, lib); | |
135 | SCM_VALIDATE_STRING (2, init); | |
136 | load_extension (lib, init); | |
137 | return SCM_UNSPECIFIED; | |
138 | } | |
139 | #undef FUNC_NAME | |
140 | ||
141 | void | |
142 | scm_init_extensions () | |
143 | { | |
144 | registered_extensions = NULL; | |
e2ab7927 | 145 | #include "libguile/extensions.x" |
e2ab7927 MV |
146 | } |
147 | ||
148 | /* | |
149 | Local Variables: | |
150 | c-file-style: "gnu" | |
151 | End: | |
152 | */ |