wait_for = integer() >= 0:

The actual timer time.

factor = integer() >= 0:

The factor when calculating the new timer time (wait_for).

incr = integer():

The increment value when calculating the new timer time (wait_for). Note that this value can be negative and that a timer restart can therefor lead to a wait_for value of zero! It is up to the user to be aware of the consequences of a wait_for value of zero.

max_retries = infinity | infinity_restartable | integer() >= 0:

The maximum number of repetitions of the timer.

Types:

Starts the Megaco application

Users may either explicitly be registered with megaco:start_user/2 and/or be statically configured by setting the application environment variable 'users' to a list of {UserMid, Config} tuples. See the function megaco:start_user/2 for details.

Types:

Stops the Megaco application

Types:

Initial configuration of a user

Requires the megaco application to be started. A user is either a Media Gateway (MG) or a Media Gateway Controller (MGC). One Erlang node may host many users.

A user is identified by its UserMid, which must be a legal Megaco MID.

Config is a list of {Item, Value} tuples. See megaco:user_info/2 about which items and values that are valid.

Types:

Delete the configuration of a user

Requires that the user does not have any active connection.

Types:

Lookup user information

The following Item's are valid:

Types:

Update information about a user

Requires that the user is started. See megaco:user_info/2 about which items and values that are valid.

Types:

Lookup information about an active connection

Requires that the connection is active.

Types:

Update information about an active connection

Requires that the connection is activated. See megaco:conn_info/2 about which items and values that are valid.

Types:

Lookup system information

The following items are valid:

Types:

This function produces a list of information about the megaco application. Such as users and their config, connections and their config, statistics and so on.

This information can be produced by the functions user_info, conn_info, system_info and get_stats but this is a simple way to get it all at once.

Types:

Establish a "virtual" connection

Activates a connection to a remote user. When this is done the connection can be used to send messages (with SendMod:send_message/2). The ControlPid is the identifier of a process that controls the connection. That process will be supervised and if it dies, this will be detected and the UserMod:handle_disconnect/2 callback function will be invoked. See the megaco_user module for more info about the callback arguments. The connection may also explicitly be deactivated by invoking megaco:disconnect/2.

The ControlPid may be the identity of a process residing on another Erlang node. This is useful when you want to distribute a user over several Erlang nodes. In such a case one of the nodes has the physical connection. When a user residing on one of the other nodes needs to send a request (with megaco:call/3 or megaco:cast/3), the message will encoded on the originating Erlang node, and then be forwarded to the node with the physical connection. When the reply arrives, it will be forwarded back to the originator. The distributed connection may explicitly be deactivated by a local call to megaco:disconnect/2 or implicitly when the physical connection is deactivated (with megaco:disconnect/2, killing the controlling process, halting the other node, ...).

The call of this function will trigger the callback function UserMod:handle_connect/2 to be invoked. See the megaco_user module for more info about the callback arguments.

A connection may be established in several ways:

An initial megaco_receive_handle record may be obtained with megaco:user_info(UserMid, receive_handle)

The send handle is provided by the preferred transport module, e.g. megaco_tcp, megaco_udp. Read the documentation about each transport module about the details.

The connect is done in two steps: first an internal connection setup and then by calling the user handle_connect callback function. The first step could result in an error with Reason = connect_reason() and the second an error with Reason = handle_connect_reason():

Extra can be any term() except the atom ignore_extra. It is passed (back) to the user via the callback function handle_connect/3.

Types:

Tear down a "virtual" connection

Causes the UserMod:handle_disconnect/2 callback function to be invoked. See the megaco_user module for more info about the callback arguments.

Types:

Sends one or more transaction request(s) and waits for the reply.

When sending one transaction in a message, Actions should be action_reqs() (UserReply will then be user_reply()). When sending several transactions in a message, Actions should be [action_reqs()] (UserReply will then be [user_reply()]). Each element of the list is part of one transaction.

For some of our codecs (not binary), it is also possible to pre-encode the actions, in which case Actions will be either a binary() or [binary()].

The function returns when the reply arrives, when the request timer eventually times out or when the outstanding requests are explicitly cancelled.

The default values of the send options are obtained by megaco:conn_info(ConnHandle, Item). But the send options above, may explicitly be overridden.

The ProtocolVersion version is the version actually encoded in the reply message.

At success(), the UserReply contains a list of 'ActionReply' records possibly containing error indications.

A message_error(), indicates that the remote user has replied with an explicit transactionError.

A user_cancel_error(), indicates that the request has been canceled by the user. reason_for_user_cancel() is the reason given in the call to the cancel function.

A send_error(), indicates that the send function of the megaco transport callback module failed to send the request. There are two separate cases: send_cancelled_reason() and send_failed_reason(). The first is the result of the send function returning {cancel, Reason} and the second is some other kind of erroneous return value. See the send_message function for more info.

An other_error(), indicates some other error such as timeout.

For more info about the extra() part of the result, see the note in the user callback module documentation.

Types:

Sends one or more transaction request(s) but does NOT wait for a reply

When sending one transaction in a message, Actions should be action_reqs(). When sending several transactions in a message, Actions should be [action_reqs()]. Each element of the list is part of one transaction.

For some of our codecs (not binary), it is also possible to pre-encode the actions, in which case Actions will be either a binary() or [binary()].

The default values of the send options are obtained by megaco:conn_info(ConnHandle, Item). But the send options above, may explicitly be overridden.

The ProtocolVersion version is the version actually encoded in the reply message.

The callback function UserMod:handle_trans_reply/4 is invoked when the reply arrives, when the request timer eventually times out or when the outstanding requests are explicitly cancelled. See the megaco_user module for more info about the callback arguments.

Given as UserData argument to UserMod:handle_trans_reply/4.

Types:

Encodes lists of action requests for one or more transaction request(s).

When encoding action requests for one transaction, Actions should be action_reqs(). When encoding action requests for several transactions, Actions should be [action_reqs()]. Each element of the list is part of one transaction.

Types:

Convert a token tag to a string

If no encoder module is given, the default is used (which is pretty).

If no or an unknown version is given, the best version is used (which is v3).

If no match is found for Tag, Result will be the empty string ([]).

Types:

Cancel all outstanding messages for this connection

This causes outstanding megaco:call/3 requests to return. The callback functions UserMod:handle_reply/4 and UserMod:handle_trans_ack/4 are also invoked where it applies. See the megaco_user module for more info about the callback arguments.

Types:

Process a received message

This function is intended to be invoked by some transport modules when get an incoming message. Which transport that actually is used is up to the user to choose.

The message is delivered as an Erlang binary and is decoded by the encoding module stated in the receive handle together with its encoding config (also in the receive handle). Depending of the outcome of the decoding various callback functions will be invoked. See megaco_user for more info about the callback arguments.

The argument Extra is just an opaque data structure passed to the user via the callback functions in the user callback module. Note however that if Extra has the value extra_undefined the argument will be ignored (same as if process_received_message/4 had been called). See the documentation for the behaviour of the callback module, megaco_user, for more info.

Note that all processing is done in the context of the calling process. A transport module could call this function via one of the spawn functions (e.g. spawn_opt). See also receive_message/4,5.

If the message cannot be decoded the following callback function will be invoked:

If the decoded message instead of transactions contains a message error, the following callback function will be invoked:

If the decoded message happens to be received before the connection is established, a new "virtual" connection is established. This is typically the case for the Media Gateway Controller (MGC) upon the first Service Change. When this occurs the following callback function will be invoked:

For each transaction request in the decoded message the following callback function will be invoked:

For each transaction reply in the decoded message the reply is returned to the user. Either the originating function megaco:call/3 will return. Or in case the originating function was megaco:case/3 the following callback function will be invoked:

When a transaction acknowledgement is received it is possible that user has decided not to bother about the acknowledgement. But in case the return value from UserMod:handle_trans_request/3 indicates that the acknowledgement is important the following callback function will be invoked:

See the megaco_user module for more info about the callback arguments.

Types:

Process a received message

This is a callback function intended to be invoked by some transport modules when get an incoming message. Which transport that actually is used is up to the user to choose.

In principle, this function calls the process_received_message/4 function via a spawn to perform the actual processing.

For further information see the process_received_message/4 function.

Types:

Parses a digit map body

Parses a digit map body, represented as a list of characters, into a list of state transitions suited to be evaluated by megaco:eval_digit_map/1,2.

Types:

Collect digit map letters according to the digit map.

When evaluating a digit map, a state machine waits for timeouts and letters reported by megaco:report_digit_event/2. The length of the various timeouts are defined in the digit_map_value() record.

When a complete sequence of valid events has been received, the result is returned as a list of letters.

There are two options for handling syntax errors (that is when an unexpected event is received when the digit map evaluator is expecting some other event). The unexpected events may either be ignored or rejected. The latter means that the evaluation is aborted and an error is returned.

Types:

Send one or more events to the event collector process.

Send one or more events to a process that is evaluating a digit map, that is a process that is executing megaco:eval_digit_map/1,2.

Note that the events $s | $S, l | $L and $z | $Z has nothing to do with the timers using the same characters.

Types:

Feed digit map collector with events and return the result

This function starts the evaluation of a digit map with megaco:eval_digit_map/1 and sends a sequence of events to it megaco:report_digit_event/2 in order to simplify testing of digit maps.

Types:

Encode (generate) an SDP construct.

If a property_parm() is found as part of the input (SDP) then it is left unchanged.

This function performs the following transformation:

Types:

Decode (parse) a property parameter construct.

When decoding property_group() or property_groups(), those property parameter constructs that cannot be decoded (either because of decode error or because they are unknown), will be returned as a two-tuple. The first element of which will be the (undecoded) property parameter and the other the actual reason. This means that the caller of this function has to expect not only sdp-records, but also this two-tuple construct.

This function performs the following transformation:

Types:

Retreive all the sdp records of type Type from the property group PG.

Types:

Utility functions used to retrieve some system and application info.

The difference between the two functions is in how they get the modules to check. versions1 uses the app-file and versions2 uses the function application:get_key.

Types:

Utility function to produce a formated printout of the versions info generated by the versions1 and versions2 functions.

The function print_version_info/0 uses the result of function version1/0 as VersionInfo.

Example:

           {ok, V} = megaco:versions1(), megaco:format_versions(V). 


        

Types:

This function is used to start megaco tracing at a given Level and direct result to the given Destination.

It starts a tracer server and then sets the proper match spec (according to Level).

In the case when Destination is File, the printable megaco trace events will be printed to the file File using plain io:format/2.

In the case when Destination is io, the printable megaco trace events will be printed on stdout using plain io:format/2.

See dbg for further information.

This function is used to stop megaco tracing.

Types:

This function is used to change the megaco trace level.

It is assumed that tracing has already been enabled (see enable_trace above).

Types:

Retreive the (SNMP) statistic counters maintained by the megaco application. The global counters handle events that cannot be attributed to a single connection (e.g. protocol errors that occur before the connection has been properly setup).

Types:

Reset all related (SNMP) statistics counters.

Types:

Tests if the Actions argument is correctly composed.

This function is only intended for testing purposes. It's supposed to have a same kind of interface as the call or cast functions (with the additions of the EncodingMod and EncodingConfig arguments). It composes a complete megaco message end attempts to encode it. The return value, will be a tuple of the composed megaco message and the encode result.

Types:

Tests if the Reply argument is correctly composed.

This function is only intended for testing purposes. It's supposed to test the actual_reply() return value of the callback functions handle_trans_request and handle_trans_long_request functions (with the additions of the EncodingMod and EncodingConfig arguments). It composes a complete megaco message end attempts to encode it. The return value, will be a tuple of the composed megaco message and the encode result.