SL_USER_REQ primitive

Purpose

Request an implementation-dependent feature from a signaling process.

Requirement

Optional for all signaling processes.

Library

The signaling interface library (libsl.a).

C syntax

typedef struct {
                SL_ID id;
                int iseq_no;
                pid_t pidCHP;
                SL_PRIMITIVE_TYPE Command;
                SL_REQUEST_PARM_ST Parms;
} SL_REQUEST_ST;
...
typedef union {
...
                struct _user_request_st{
                    size_t sizetLength;
                    int command;
                    int iChannelNo;
                    int iVpackNo;
                    unsigned char data[SL_USER_DATA_LEN];
                } user_request_st;
...
} SL_REQUEST_PARM_ST;

Description

The SL_USER_REQ primitive is sent by a custom server process to the signaling process. This primitive allows any signaling process to provide implementation-dependent primitives.

The interpretation and usage of the SL_USER_REQ primitive is up to the signaling process. If the signaling process does not support the SL_USER_REQ primitive, it should respond by issuing sl_send_confirm(), specifying an SL_USER_CNF primitive with ReplyCode set to SL_REPLY_NOT_IMPLEMENTED.

Any implementation-dependent primitives, implemented using SL_USER_REQ, should be documented by the supplier of the signaling process.

Corresponding state table action

None.

Parameters

id: Eye-catcher that identifies the structure as containing a request primitive. Must be set to SLID_REQUEST_ST.
iseq_no: The sequence number of the primitive. This field must be set to 0 when the primitive is sent to Blueworx Voice Response; the actual sequence number is allocated by Blueworx Voice Response, and is available to the sender on return from sl_send_request(). The field is set when the primitive is received from Blueworx Voice Response by the signaling process.
pidCHP: The process id of the sending process. The signaling process should use this value to set the pidCHP field of the corresponding SL_USER_CNF primitive.
Command.id: The primitive that the structure contains. Must be set to SL_USER_REQ.
Parms.user_request_st.sizetLength: Must be set to sizeof(struct _user_request_st).
Parms.user_request_st.command: This field is provided for use by the signaling process to differentiate implementation-dependent primitives. The values of this field are implementation-dependent, and are defined by the provider of the signaling process.
Parms.user_request_st.iChannelNo: Identifies the channel, in the range SL_MIN_CHANNEL_ID to SL_MAX_CHANNEL_ID (see Pack and channel numbers).
Parms.user_request_st.iVpackNo: Identifies the trunk, in the range SL_MIN_TRUNK_ID to SL_MAX_TRUNK_ID (see Pack and channel numbers).
Parms.user_request_st.data: Up to SL_USER_DATA_LEN bytes of implementation-dependent data. The interpretation of this field depends on the value of Parms.user_request_st.command, and is defined by the provider of the signaling process.