(mix)monitor: Add options to enable a periodic beep

Add an option to enable a periodic beep to be played into a call if it
is being recorded.  If enabled, it uses the PERIODIC_HOOK() function
internally to play the 'beep' prompt into the call at a specified
interval.  This option is provided for both Monitor() and
MixMonitor().

Review: https://reviewboard.asterisk.org/r/3424/


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@412427 65c4cc65-6c06-0410-ace0-fbb531ad65f3

include/asterisk/beep.h

@@ -0,0 +1,45 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2014, Russell Bryant
+ *
+ * Russell Bryant <russell@russellbryant.net>
+ *
+ * See http://www.asterisk.org for more information about
+ * the Asterisk project. Please do not directly contact
+ * any of the maintainers of this project for assistance;
+ * the project provides a web site, mailing lists and IRC
+ * channels for your use.
+ *
+ * This program is free software, distributed under the terms of
+ * the GNU General Public License Version 2. See the LICENSE file
+ * at the top of the source tree.
+ */
+
+/*!
+ * \file
+ * \brief Periodic beeps into the audio of a call
+ */
+
+#ifndef _ASTERISK_BEEP_H
+#define _ASTERISK_BEEP_H
+
+#include "asterisk/optional_api.h"
+
+#if defined(__cplusplus) || defined(c_plusplus)
+extern "C" {
+#endif
+
+AST_OPTIONAL_API(int, ast_beep_start,
+		(struct ast_channel *chan, unsigned int interval, char *beep_id, size_t len),
+		{ return -1; });
+
+AST_OPTIONAL_API(int, ast_beep_stop,
+		(struct ast_channel *chan, const char *beep_id),
+		{ return -1; });
+
+#if defined(__cplusplus) || defined(c_plusplus)
+}
+#endif
+
+#endif /* _ASTERISK_BEEP_H */