Redesigned 'optional API' support.

This patch provides a new implementation of the optional API support defined
in asterisk/optional_api.h; this new version provides solves compatibility
issues with the use of linker version scripts for suppressing global symbols.
In addition, there is now a functional (and tested!) implementation for Mac OS/X,
so module writers no longer need to use special tests before calling optional
API functions. All future implementations must provide these same semantics,
so that module writers can rely on them.



git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@200519 65c4cc65-6c06-0410-ace0-fbb531ad65f3

6 files changed, 216 insertions, 104 deletions

diff --git a/include/asterisk/agi.h b/include/asterisk/agi.h
index c44aafc3f..210b895ad 100644
--- a/include/asterisk/agi.h
+++ b/include/asterisk/agi.h
@@ -72,7 +72,8 @@ typedef struct agi_command {
  * \return 1 on success, 0 if the command is already registered
  *
  */
-AST_OPTIONAL_API(int, ast_agi_register, (struct ast_module *mod, agi_command *cmd),
+AST_OPTIONAL_API(int, ast_agi_register,
+		 (struct ast_module *mod, agi_command *cmd),
 		 { return AST_OPTIONAL_API_UNAVAILABLE; });
 
 /*!
@@ -85,7 +86,8 @@ AST_OPTIONAL_API(int, ast_agi_register, (struct ast_module *mod, agi_command *cm
  * \return 1 on success, 0 if the command was not already registered
  *
  */
-AST_OPTIONAL_API(int, ast_agi_unregister, (struct ast_module *mod, agi_command *cmd),
+AST_OPTIONAL_API(int, ast_agi_unregister,
+		 (struct ast_module *mod, agi_command *cmd),
 		 { return AST_OPTIONAL_API_UNAVAILABLE; });
 
 /*!
@@ -103,7 +105,8 @@ AST_OPTIONAL_API(int, ast_agi_unregister, (struct ast_module *mod, agi_command *
  * will be unregistered. In other words, this function registers all the provided commands, or none
  * of them.
  */
-AST_OPTIONAL_API(int, ast_agi_register_multiple, (struct ast_module *mod, struct agi_command *cmd, unsigned int len),
+AST_OPTIONAL_API(int, ast_agi_register_multiple,
+		 (struct ast_module *mod, struct agi_command *cmd, unsigned int len),
 		 { return AST_OPTIONAL_API_UNAVAILABLE; });
 
 /*!
@@ -120,7 +123,8 @@ AST_OPTIONAL_API(int, ast_agi_register_multiple, (struct ast_module *mod, struct
  * \note If any command fails to unregister, this function will continue to unregister the
  * remaining commands in the array; it will not reregister the already-unregistered commands.
  */
-AST_OPTIONAL_API(int, ast_agi_unregister_multiple, (struct ast_module *mod, struct agi_command *cmd, unsigned int len),
+AST_OPTIONAL_API(int, ast_agi_unregister_multiple,
+		 (struct ast_module *mod, struct agi_command *cmd, unsigned int len),
 		 { return AST_OPTIONAL_API_UNAVAILABLE; });
 
 /*!
@@ -134,7 +138,8 @@ AST_OPTIONAL_API(int, ast_agi_unregister_multiple, (struct ast_module *mod, stru
  * \return 0 for success, -1 for failure, AST_OPTIONAL_API_UNAVAILABLE if res_agi is not loaded
  *
  */
-AST_OPTIONAL_API_ATTR(int, format(printf, 3, 4), ast_agi_send, (int fd, struct ast_channel *chan, char *fmt, ...),
+AST_OPTIONAL_API_ATTR(int, format(printf, 3, 4), ast_agi_send,
+		      (int fd, struct ast_channel *chan, char *fmt, ...),
 		      { return AST_OPTIONAL_API_UNAVAILABLE; });
 
 #if defined(__cplusplus) || defined(c_plusplus)
diff --git a/include/asterisk/autoconfig.h.in b/include/asterisk/autoconfig.h.in
index 33b6d2f49..e11ea6b1f 100644
--- a/include/asterisk/autoconfig.h.in
+++ b/include/asterisk/autoconfig.h.in
@@ -94,9 +94,6 @@
 /* Define to 1 if you have the `atexit' function. */
 #undef HAVE_ATEXIT
 
-/* Define to 1 if your GCC C compiler supports the 'alias' attribute. */
-#undef HAVE_ATTRIBUTE_alias
-
 /* Define to 1 if your GCC C compiler supports the 'always_inline' attribute.
    */
 #undef HAVE_ATTRIBUTE_always_inline
@@ -123,12 +120,12 @@
    attribute. */
 #undef HAVE_ATTRIBUTE_warn_unused_result
 
-/* Define to 1 if your GCC C compiler supports the 'weak' attribute. */
-#undef HAVE_ATTRIBUTE_weak
-
 /* Define to 1 if your GCC C compiler supports the 'weak_import' attribute. */
 #undef HAVE_ATTRIBUTE_weak_import
 
+/* Define to 1 if your GCC C compiler supports the 'weakref' attribute. */
+#undef HAVE_ATTRIBUTE_weakref
+
 /* Define this to indicate the ${BKTR_DESCRIP} library */
 #undef HAVE_BKTR
 
@@ -1214,9 +1211,6 @@
 /* Define to the version of this package. */
 #undef PACKAGE_VERSION
 
-/* Define to 1 if the C compiler supports function prototypes. */
-#undef PROTOTYPES
-
 /* Define to necessary symbol if this constant uses a non-standard name on
    your system. */
 #undef PTHREAD_CREATE_JOINABLE
@@ -1233,11 +1227,6 @@
 /* Define to the type of arg 5 for `select'. */
 #undef SELECT_TYPE_ARG5
 
-/* Define to 1 if the `setvbuf' function takes the buffering type as its
-   second argument and the buffer pointer as the third, as on System V before
-   release 3. */
-#undef SETVBUF_REVERSED
-
 /* The size of `int', as computed by sizeof. */
 #undef SIZEOF_INT
 
@@ -1258,20 +1247,30 @@
 /* Define to 1 if your <sys/time.h> declares `struct tm'. */
 #undef TM_IN_SYS_TIME
 
-/* Define to 1 if on AIX 3.
-   System headers sometimes define this.
-   We just want to avoid a redefinition error message.  */
+/* Enable extensions on AIX 3, Interix.  */
 #ifndef _ALL_SOURCE
 # undef _ALL_SOURCE
 #endif
-
-/* Number of bits in a file offset, on hosts where this is settable. */
-#undef _FILE_OFFSET_BITS
-
 /* Enable GNU extensions on systems that have them.  */
 #ifndef _GNU_SOURCE
 # undef _GNU_SOURCE
 #endif
+/* Enable threading extensions on Solaris.  */
+#ifndef _POSIX_PTHREAD_SEMANTICS
+# undef _POSIX_PTHREAD_SEMANTICS
+#endif
+/* Enable extensions on HP NonStop.  */
+#ifndef _TANDEM_SOURCE
+# undef _TANDEM_SOURCE
+#endif
+/* Enable general extensions on Solaris.  */
+#ifndef __EXTENSIONS__
+# undef __EXTENSIONS__
+#endif
+
+
+/* Number of bits in a file offset, on hosts where this is settable. */
+#undef _FILE_OFFSET_BITS
 
 /* Define to 1 to make fseeko visible on some hosts (e.g. glibc 2.2). */
 #undef _LARGEFILE_SOURCE
@@ -1289,20 +1288,6 @@
 /* Define to 1 if you need to in order for `stat' and other things to work. */
 #undef _POSIX_SOURCE
 
-/* Enable extensions on Solaris.  */
-#ifndef __EXTENSIONS__
-# undef __EXTENSIONS__
-#endif
-#ifndef _POSIX_PTHREAD_SEMANTICS
-# undef _POSIX_PTHREAD_SEMANTICS
-#endif
-#ifndef _TANDEM_SOURCE
-# undef _TANDEM_SOURCE
-#endif
-
-/* Define like PROTOTYPES; this can be used by system headers. */
-#undef __PROTOTYPES
-
 /* Define to empty if `const' does not conform to ANSI C. */
 #undef const
 
diff --git a/include/asterisk/compiler.h b/include/asterisk/compiler.h
index 15a750f9c..b2db7ffdb 100644
--- a/include/asterisk/compiler.h
+++ b/include/asterisk/compiler.h
@@ -68,16 +68,4 @@
 /* Some older version of GNU gcc (3.3.5 on OpenBSD 4.3 for example) dont like 'NULL' as sentinel */
 #define SENTINEL ((char *)NULL)
 
-#ifdef HAVE_ATTRIBUTE_weak
-#define attribute_weak __attribute__((weak))
-#else
-#define attribute_weak
-#endif
-
-#ifdef HAVE_ATTRIBUTE_weak_import
-#define attribute_weak_import __attribute__((weak_import))
-#else
-#define attribute_weak_import
-#endif
-
 #endif /* _ASTERISK_COMPILER_H */
diff --git a/include/asterisk/monitor.h b/include/asterisk/monitor.h
index 4014939bb..e29622ea8 100644
--- a/include/asterisk/monitor.h
+++ b/include/asterisk/monitor.h
@@ -51,27 +51,34 @@ struct ast_channel_monitor {
 };
 
 /* Start monitoring a channel */
-AST_OPTIONAL_API(int, ast_monitor_start, (struct ast_channel *chan, const char
-	*format_spec, const char *fname_base, int need_lock, int stream_action),
-	{ return -1; });
+AST_OPTIONAL_API(int, ast_monitor_start,
+		 (struct ast_channel *chan, const char *format_spec,
+		  const char *fname_base, int need_lock, int stream_action),
+		 { return -1; });
 
 /* Stop monitoring a channel */
-AST_OPTIONAL_API(int, ast_monitor_stop, (struct ast_channel *chan, int
-	need_lock), { return -1; });
+AST_OPTIONAL_API(int, ast_monitor_stop,
+		 (struct ast_channel *chan, int need_lock),
+		 { return -1; });
 
 /* Change monitoring filename of a channel */
-AST_OPTIONAL_API(int, ast_monitor_change_fname, (struct ast_channel *chan,
-	const char *fname_base, int need_lock), { return -1; });
+AST_OPTIONAL_API(int, ast_monitor_change_fname,
+		 (struct ast_channel *chan, const char *fname_base,
+		  int need_lock),
+		 { return -1; });
 
-AST_OPTIONAL_API(void, ast_monitor_setjoinfiles, (struct ast_channel *chan,
-	int turnon), { return; });
+AST_OPTIONAL_API(void, ast_monitor_setjoinfiles,
+		 (struct ast_channel *chan, int turnon),
+		 { return; });
 
 /* Pause monitoring of a channel */
-AST_OPTIONAL_API(int, ast_monitor_pause, (struct ast_channel *chan),
-	{ return -1; });
+AST_OPTIONAL_API(int, ast_monitor_pause,
+		 (struct ast_channel *chan),
+		 { return -1; });
 
 /* Unpause monitoring of a channel */
-AST_OPTIONAL_API(int, ast_monitor_unpause, (struct ast_channel *chan),
-	{ return -1; });
+AST_OPTIONAL_API(int, ast_monitor_unpause,
+		 (struct ast_channel *chan),
+		 { return -1; });
 
 #endif /* _ASTERISK_MONITOR_H */
diff --git a/include/asterisk/optional_api.h b/include/asterisk/optional_api.h
index 1af596ec1..df875a849 100644
--- a/include/asterisk/optional_api.h
+++ b/include/asterisk/optional_api.h
@@ -32,14 +32,14 @@
  *
  * To accomodate this situation, the AST_OPTIONAL_API macro allows an API
  * function to be declared in a special way, if Asterisk being built on a
- * platform that supports the GCC 'weak' and 'alias' attributes. If so,
- * the API function is actually a weak symbol, which means if the provider
- * of the API is not loaded, the symbol can still be referenced (unlike a
+ * platform that supports special compiler and dynamic linker attributes.
+ * If so the API function will actually be a weak symbol, which means if the
+ * provider of the API is not loaded, the symbol can still be referenced (unlike a
  * strong symbol, which would cause an immediate fault if not defined when
  * referenced), but it will return NULL signifying the linker/loader was
  * not able to resolve the symbol. In addition, the macro defines a hidden
  * 'stub' version of the API call, using a provided function body, and uses
- * the alias attribute to make the API function symbol actually resolve to
+ * various methods to make the API function symbol actually resolve to
  * that hidden stub, but only when the *real* provider of the symbol has
  * not been found.
  *
@@ -57,13 +57,25 @@
  * safely know that the API is not available, and to avoid using any
  * other APIs from the not-present provider.
  *
+ * In addition to this declaration in the header file, the actual definition of
+ * the API function must use the AST_OPTIONAL_API_NAME macro to (possibly)
+ * modify the real name of the API function, depending on the specific
+ * implementation requirements. The corresponding example from res_agi.c:
+ *
+ * \code
+ * int AST_OPTIONAL_API_NAME(ast_agi_register)(struct ast_module *mod, agi_command *cmd)
+ * {
+ * ...
+ * }
+ * \endcode
+ *
  * In the module providing the API, the AST_OPTIONAL_API macro must
  * be informed that it should not build the hidden stub function or
  * apply special aliases to the function prototype; this can be done
  * by defining AST_API_MODULE just before including the header file
  * containing the AST_OPTIONAL_API macro calls.
  *
- * \note If the GCC 'weak' and 'alias' attributes are not available,
+ * \note If the platform does not provide adequate resources,
  * then the AST_OPTIONAL_API macro will result in a non-optional function
  * definition; this means that any consumers of the API functions so
  * defined will require that the provider of the API functions be
@@ -83,17 +95,115 @@
  */
 #define AST_OPTIONAL_API_UNAVAILABLE	INT_MIN
 
-#if defined(HAVE_ATTRIBUTE_weak_import) && !defined(AST_API_MODULE)
-#define AST_OPTIONAL_API(result, name, proto, stub)	result name proto __attribute__((weak_import));
-#define AST_OPTIONAL_API_ATTR(result, attr, name, proto, stub)	result name proto __attribute__((weak_import,attr));
-#elif defined(HAVE_ATTRIBUTE_weak) && defined(HAVE_ATTRIBUTE_alias) && !defined(AST_API_MODULE) && !defined(HAVE_ATTRIBUTE_weak_import)
-#define AST_OPTIONAL_API(result, name, proto, stub)	\
-	static result __##name proto stub;		\
-	result __attribute__((weak, alias("__" __stringify(name)))) name proto;
-#define AST_OPTIONAL_API_ATTR(result, attr, name, proto, stub)		\
-	static result __attribute__((attr)) __##name proto stub;	\
-	result __attribute__((weak, alias("__" __stringify(name)), attr)) name proto;
+
+#if defined(HAVE_ATTRIBUTE_weak_import)
+
+/*
+ * This is the Darwin (Mac OS/X) implementation, that only provides the
+ * 'weak_import' compiler attribute for weak symbols. On this platform,
+ *
+ * - The module providing the API will only provide a '__' prefixed version
+ *   of the API function to other modules (this will be hidden from the other
+ *   modules by the macros), so any modules compiled against older versions
+ *   of the module that provided a non-prefixed version of the API function
+ *   will fail to link at runtime.
+ * - In the API module itself, access to the API function without using a
+ *   prefixed name is provided by a static pointer variable that holds the
+ *   function address.
+ * - 'Consumer' modules of the API will use a combination of a weak_import
+ *   symbol, a local stub function, a pointer variable and a constructor function
+ *   (which initializes that pointer variable as the module is being loaded)
+ *   to provide safe, optional access to the API function without any special
+ *   code being required.
+ */
+
+#define AST_OPTIONAL_API_NAME(name) __##name
+
+#if defined(AST_API_MODULE)
+
+#define AST_OPTIONAL_API(result, name, proto, stub) \
+	result AST_OPTIONAL_API_NAME(name) proto; \
+	static attribute_unused typeof(AST_OPTIONAL_API_NAME(name)) * const name = AST_OPTIONAL_API_NAME(name);
+
+#define AST_OPTIONAL_API_ATTR(result, attr, name, proto, stub)	\
+	result __attribute__((attr)) AST_OPTIONAL_API_NAME(name) proto; \
+	static attribute_unused typeof(AST_OPTIONAL_API_NAME(name)) * const name = AST_OPTIONAL_API_NAME(name);
+
+#else
+
+#define AST_OPTIONAL_API(result, name, proto, stub) \
+	static result __stub__##name proto stub; \
+	__attribute__((weak_import)) typeof(__stub__##name) AST_OPTIONAL_API_NAME(name); \
+	static attribute_unused typeof(__stub__##name) * name; \
+	static void __attribute__((constructor)) __init__##name(void) { name = AST_OPTIONAL_API_NAME(name) ? : __stub__##name; }
+
+#define AST_OPTIONAL_API_ATTR(result, attr, name, proto, stub) \
+	static __attribute__((attr)) result __stub__##name proto stub; \
+	__attribute__((attr, weak_import)) typeof(__stub__##name) AST_OPTIONAL_API_NAME(name); \
+	static attribute_unused __attribute__((attr)) typeof(__stub__##name) * name; \
+	static void __attribute__((constructor)) __init__##name(void) { name = AST_OPTIONAL_API_NAME(name) ? : __stub__##name; }
+
+
+#endif
+
+/* End of Darwin (Mac OS/X) implementation */
+
+#elif defined(HAVE_ATTRIBUTE_weakref)
+
+/*
+ * This is the generic GCC implementation, used when the 'weakref'
+ * compiler attribute is available. On these platforms:
+ *
+ * - The module providing the API will provide a '__' prefixed version
+ *   of the API function to other modules (this will be hidden from the other
+ *   modules by the macros), and also a non-prefixed alias so that modules
+ *   compiled against older versions of the module that provided a non-prefixed
+ *    version of the API function will continue to link properly.
+ * - In the API module itself, access to the API function without using a
+ *   prefixed name is provided by the non-prefixed alias described above.
+ * - 'Consumer' modules of the API will use a combination of a weakref
+ *   symbol, a local stub function, a pointer variable and a constructor function
+ *   (which initializes that pointer variable as the module is being loaded)
+ *   to provide safe, optional access to the API function without any special
+ *   code being required.
+ */
+
+#define AST_OPTIONAL_API_NAME(name) __##name
+
+#if defined(AST_API_MODULE)
+
+#define AST_OPTIONAL_API(result, name, proto, stub) \
+	result AST_OPTIONAL_API_NAME(name) proto; \
+	__attribute__((alias(__stringify(AST_OPTIONAL_API_NAME(name))))) typeof(AST_OPTIONAL_API_NAME(name)) name;
+
+#define AST_OPTIONAL_API_ATTR(result, attr, name, proto, stub)	\
+	result __attribute__((attr)) AST_OPTIONAL_API_NAME(name) proto; \
+	__attribute__((alias(__stringify(AST_OPTIONAL_API_NAME(name))))) typeof(AST_OPTIONAL_API_NAME(name)) name;
+
+#else
+
+#define AST_OPTIONAL_API(result, name, proto, stub) \
+	static result __stub__##name proto stub; \
+	static __attribute__((weakref(__stringify(AST_OPTIONAL_API_NAME(name))))) typeof(__stub__##name) __ref__##name; \
+	static attribute_unused typeof(__stub__##name) * name; \
+	static void __attribute__((constructor)) __init__##name(void) { name = __ref__##name ? : __stub__##name; }
+
+#define AST_OPTIONAL_API_ATTR(result, attr, name, proto, stub) \
+	static __attribute__((attr)) result __stub__##name proto stub; \
+	static __attribute__((attr, weakref(__stringify(AST_OPTIONAL_API_NAME(name))))) typeof(__stub__##name) __ref__##name; \
+	static attribute_unused __attribute__((attr)) typeof(__stub__##name) * name; \
+	static void __attribute__((constructor)) __init__##name(void) { name = __ref__##name ? : __stub__##name; }
+
+#endif
+
+/* End of GCC implementation */
+
 #else
+
+/* This is the non-optional implementation. */
+
+#define AST_OPTIONAL_API_NAME(name) name
+
 /*!
  * \brief Define an optional API function
  *
@@ -108,7 +218,8 @@
  *                  { return AST_OPTIONAL_API_UNAVAILABLE; });
  * \endcode		 
  */
-#define AST_OPTIONAL_API(result, name, proto, stub) result name proto;
+#define AST_OPTIONAL_API(result, name, proto, stub) result AST_OPTIONAL_API_NAME(name) proto
+
 /*!
  * \brief Define an optional API function with compiler attributes
  *
@@ -118,7 +229,10 @@
  * \param proto The prototype (arguments) of the function
  * \param stub The code block that will be used by the hidden stub when needed
  */
-#define AST_OPTIONAL_API_ATTR(result, attr, name, proto, stub) result __attribute__((attr)) name proto;
+#define AST_OPTIONAL_API_ATTR(result, attr, name, proto, stub) result __attribute__((attr)) AST_OPTIONAL_API_NAME(name) proto
+
+/* End of non-optional implementation */
+
 #endif
 
 #undef AST_API_MODULE
diff --git a/include/asterisk/smdi.h b/include/asterisk/smdi.h
index 9dbec6288..9d80c9071 100644
--- a/include/asterisk/smdi.h
+++ b/include/asterisk/smdi.h
@@ -85,8 +85,9 @@ struct ast_smdi_md_message {
  */
 struct ast_smdi_interface;
 
-AST_OPTIONAL_API(void, ast_smdi_interface_unref, (struct ast_smdi_interface
-	*iface), { return; });
+AST_OPTIONAL_API(void, ast_smdi_interface_unref,
+		 (struct ast_smdi_interface *iface),
+		 { return; });
 
 /*! 
  * \brief Get the next SMDI message from the queue.
@@ -98,8 +99,9 @@ AST_OPTIONAL_API(void, ast_smdi_interface_unref, (struct ast_smdi_interface
  *
  * \return the next SMDI message, or NULL if there were no pending messages.
  */
-AST_OPTIONAL_API(struct ast_smdi_md_message *, ast_smdi_md_message_pop, (struct
-	ast_smdi_interface *iface), { return NULL; });
+AST_OPTIONAL_API(struct ast_smdi_md_message *, ast_smdi_md_message_pop,
+		 (struct ast_smdi_interface *iface),
+		 { return NULL; });
 
 /*!
  * \brief Get the next SMDI message from the queue.
@@ -114,7 +116,8 @@ AST_OPTIONAL_API(struct ast_smdi_md_message *, ast_smdi_md_message_pop, (struct
  * the timeout has expired.
  */
 AST_OPTIONAL_API(struct ast_smdi_md_message *, ast_smdi_md_message_wait,
-	(struct ast_smdi_interface *iface, int timeout), { return NULL; });
+		 (struct ast_smdi_interface *iface, int timeout),
+		 { return NULL; });
 
 /*!
  * \brief Put an SMDI message back in the front of the queue.
@@ -125,8 +128,9 @@ AST_OPTIONAL_API(struct ast_smdi_md_message *, ast_smdi_md_message_wait,
  * should be used if a message was popped but is not going to be processed for
  * some reason, and the message needs to be returned to the queue.
  */
-AST_OPTIONAL_API(void, ast_smdi_md_message_putback, (struct ast_smdi_interface
-	*iface, struct ast_smdi_md_message *msg), { return; });
+AST_OPTIONAL_API(void, ast_smdi_md_message_putback,
+		 (struct ast_smdi_interface *iface, struct ast_smdi_md_message *msg),
+		 { return; });
 
 /*!
  * \brief Get the next SMDI message from the queue.
@@ -139,7 +143,8 @@ AST_OPTIONAL_API(void, ast_smdi_md_message_putback, (struct ast_smdi_interface
  * \return the next SMDI message, or NULL if there were no pending messages.
  */
 AST_OPTIONAL_API(struct ast_smdi_mwi_message *, ast_smdi_mwi_message_pop,
-	(struct ast_smdi_interface *iface), { return NULL; });
+		 (struct ast_smdi_interface *iface),
+		 { return NULL; });
 
 /*!
  * \brief Get the next SMDI message from the queue.
@@ -154,10 +159,12 @@ AST_OPTIONAL_API(struct ast_smdi_mwi_message *, ast_smdi_mwi_message_pop,
  * the timeout has expired.
  */
 AST_OPTIONAL_API(struct ast_smdi_mwi_message *, ast_smdi_mwi_message_wait,
-	(struct ast_smdi_interface *iface, int timeout), { return NULL; });
-AST_OPTIONAL_API(struct ast_smdi_mwi_message *,
-	ast_smdi_mwi_message_wait_station, (struct ast_smdi_interface *iface, int
-	timeout, const char *station), { return NULL; });
+		 (struct ast_smdi_interface *iface, int timeout),
+		 { return NULL; });
+
+AST_OPTIONAL_API(struct ast_smdi_mwi_message *, ast_smdi_mwi_message_wait_station,
+		 (struct ast_smdi_interface *iface, int	timeout, const char *station),
+		 { return NULL; });
 
 /*!
  * \brief Put an SMDI message back in the front of the queue.
@@ -168,8 +175,9 @@ AST_OPTIONAL_API(struct ast_smdi_mwi_message *,
  * should be used if a message was popped but is not going to be processed for
  * some reason, and the message needs to be returned to the queue.
  */
-AST_OPTIONAL_API(void, ast_smdi_mwi_message_putback, (struct ast_smdi_interface
-	*iface, struct ast_smdi_mwi_message *msg), { return; });
+AST_OPTIONAL_API(void, ast_smdi_mwi_message_putback,
+		 (struct ast_smdi_interface *iface, struct ast_smdi_mwi_message *msg),
+		 { return; });
 
 /*!
  * \brief Find an SMDI interface with the specified name.
@@ -180,30 +188,35 @@ AST_OPTIONAL_API(void, ast_smdi_mwi_message_putback, (struct ast_smdi_interface
  * #ASTOBJ_UNREF(iface, ast_smdi_interface_destroy).
  */
 AST_OPTIONAL_API(struct ast_smdi_interface *, ast_smdi_interface_find,
-	(const char *iface_name), { return NULL; });
+		 (const char *iface_name),
+		 { return NULL; });
 
 /*!
  * \brief Set the MWI indicator for a mailbox.
  * \param iface the interface to use.
  * \param mailbox the mailbox to use.
  */
-AST_OPTIONAL_API(int, ast_smdi_mwi_set, (struct ast_smdi_interface *iface,
-	const char *mailbox), { return -1; });
+AST_OPTIONAL_API(int, ast_smdi_mwi_set,
+		 (struct ast_smdi_interface *iface, const char *mailbox),
+		 { return -1; });
 
 /*! 
  * \brief Unset the MWI indicator for a mailbox.
  * \param iface the interface to use.
  * \param mailbox the mailbox to use.
  */
-AST_OPTIONAL_API(int, ast_smdi_mwi_unset, (struct ast_smdi_interface *iface,
-	const char *mailbox), { return -1; });
+AST_OPTIONAL_API(int, ast_smdi_mwi_unset,
+		 (struct ast_smdi_interface *iface, const char *mailbox),
+		 { return -1; });
 
 /*! \brief ast_smdi_md_message destructor. */
 AST_OPTIONAL_API(void, ast_smdi_md_message_destroy,
-	(struct ast_smdi_md_message *msg), { return; });
+		 (struct ast_smdi_md_message *msg),
+		 { return; });
 
 /*! \brief ast_smdi_mwi_message destructor. */
-AST_OPTIONAL_API(void, ast_smdi_mwi_message_destroy, (struct
-	ast_smdi_mwi_message *msg), { return; });
+AST_OPTIONAL_API(void, ast_smdi_mwi_message_destroy,
+		 (struct ast_smdi_mwi_message *msg),
+		 { return; });
 
 #endif /* !ASTERISK_SMDI_H */