Detect if the installed gcc version supports the warn_unused_result attribute.

Reported by mvanbaak via IRC -dev.


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@123988 65c4cc65-6c06-0410-ace0-fbb531ad65f3

configure.ac

@@ -441,6 +441,7 @@ AST_GCC_ATTRIBUTE(unused)
 AST_GCC_ATTRIBUTE(always_inline)
 AST_GCC_ATTRIBUTE(deprecated)
 AST_GCC_ATTRIBUTE(sentinel)
+AST_GCC_ATTRIBUTE(warn_unused_result)
 
 AC_MSG_CHECKING(for -ffunction-sections support)
 saved_CFLAGS="${CFLAGS}"

include/asterisk/autoconfig.h.in

@@ -113,6 +113,10 @@
 /* Define to 1 if your GCC C compiler supports the 'unused' attribute. */
 #undef HAVE_ATTRIBUTE_unused
 
+/* Define to 1 if your GCC C compiler supports the 'warn_unused_result'
+   attribute. */
+#undef HAVE_ATTRIBUTE_warn_unused_result
+
 /* Define this to indicate the ${BKTR_DESCRIP} library */
 #undef HAVE_BKTR
 

include/asterisk/compiler.h

@@ -59,4 +59,10 @@
 #define attribute_sentinel
 #endif
 
+#ifdef HAVE_ATTRIBUTE_warn_unused_result
+#define attribute_warn_unused_result __attribute__((warn_unused_result))
+#else
+#define attribute_warn_unused_result
+#endif
+
 #endif /* _ASTERISK_COMPILER_H */

include/asterisk/logger.h

@@ -83,8 +83,8 @@ void __ast_verbose(const char *file, int line, const char *func, const char *fmt
 void ast_child_verbose(int level, const char *fmt, ...)
 	__attribute__ ((format (printf, 2, 3)));
 
-int ast_register_verbose(void (*verboser)(const char *string)) __attribute__((warn_unused_result));
-int ast_unregister_verbose(void (*verboser)(const char *string)) __attribute__((warn_unused_result));
+int ast_register_verbose(void (*verboser)(const char *string)) attribute_warn_unused_result;
+int ast_unregister_verbose(void (*verboser)(const char *string)) attribute_warn_unused_result;
 
 void ast_console_puts(const char *string);
 

include/asterisk/sched.h

@@ -149,7 +149,7 @@ char *ast_sched_report(struct sched_context *con, char *buf, int bufsiz, struct
  * \param data data to pass to the callback
  * \return Returns a schedule item ID on success, -1 on failure
  */
-int ast_sched_add(struct sched_context *con, int when, ast_sched_cb callback, const void *data) __attribute__((warn_unused_result));
+int ast_sched_add(struct sched_context *con, int when, ast_sched_cb callback, const void *data) attribute_warn_unused_result;
 
 /*!
  * \brief replace a scheduler entry
@@ -162,7 +162,7 @@ int ast_sched_add(struct sched_context *con, int when, ast_sched_cb callback, co
  * \retval -1 failure
  * \retval otherwise, returns scheduled item ID
  */
-int ast_sched_replace(int old_id, struct sched_context *con, int when, ast_sched_cb callback, const void *data) __attribute__((warn_unused_result));
+int ast_sched_replace(int old_id, struct sched_context *con, int when, ast_sched_cb callback, const void *data) attribute_warn_unused_result;
 
 /*!Adds a scheduled event with rescheduling support
  * \param con Scheduler context to add
@@ -177,7 +177,7 @@ int ast_sched_replace(int old_id, struct sched_context *con, int when, ast_sched
  * If callback returns 0, no further events will be re-scheduled
  * \return Returns a schedule item ID on success, -1 on failure
  */
-int ast_sched_add_variable(struct sched_context *con, int when, ast_sched_cb callback, const void *data, int variable) __attribute__((warn_unused_result));
+int ast_sched_add_variable(struct sched_context *con, int when, ast_sched_cb callback, const void *data, int variable) attribute_warn_unused_result;
 
 /*!
  * \brief replace a scheduler entry
@@ -190,7 +190,7 @@ int ast_sched_add_variable(struct sched_context *con, int when, ast_sched_cb cal
  * \retval -1 failure
  * \retval otherwise, returns scheduled item ID
  */
-int ast_sched_replace_variable(int old_id, struct sched_context *con, int when, ast_sched_cb callback, const void *data, int variable) __attribute__((warn_unused_result));
+int ast_sched_replace_variable(int old_id, struct sched_context *con, int when, ast_sched_cb callback, const void *data, int variable) attribute_warn_unused_result;
 
 	
 /*! \brief Find a sched structure and return the data field associated with it. 
@@ -210,7 +210,7 @@ const void *ast_sched_find_data(struct sched_context *con, int id);
  * \param id ID of the scheduled item to delete
  * \return Returns 0 on success, -1 on failure
  */
-int ast_sched_del(struct sched_context *con, int id) __attribute__((warn_unused_result));
+int ast_sched_del(struct sched_context *con, int id) attribute_warn_unused_result;
 
 /*! \brief Determines number of seconds until the next outstanding event to take place
  * Determine the number of seconds until the next outstanding event
@@ -221,7 +221,7 @@ int ast_sched_del(struct sched_context *con, int id) __attribute__((warn_unused_
  * \return Returns "-1" if there is nothing there are no scheduled events
  * (and thus the poll should not timeout)
  */
-int ast_sched_wait(struct sched_context *con) __attribute__((warn_unused_result));
+int ast_sched_wait(struct sched_context *con) attribute_warn_unused_result;
 
 /*! \brief Runs the queue
  * \param con Scheduling context to run