Start Channel (MQTT)

The Start Channel (MQCMD_START_CHANNEL) command starts an IBM MQ channel. This command can be issued to a channel of type MQCHT_MQTT.

Required parameters

ChannelName (MQCFST)

Channel name (parameter identifier: MQCACH_CHANNEL_NAME).

The name of the channel to be started. The maximum length of the string is MQ_CHANNEL_NAME_LENGTH.

This parameter is required for all channel types including MQTT channels.

ChannelType (MQCFIN)

The type of channel (parameter identifier: MQIACH_CHANNEL_TYPE). This parameter is currently only used with MQTT Telemetry channels, and is required when starting a Telemetry channel. The only value that can currently be given to the parameter is MQCHT_MQTT.

Error codes

This command might return the following error codes in the response format header, in addition to the values shown in Error codes applicable to all commands.

Reason (MQLONG)

The value can be any of the following values:

MQRCCF_PARM_SYNTAX_ERROR

The parameter specified contained a syntax error.

MQRCCF_PARM_MISSING

Parameters are missing.

MQRCCF_CHANNEL_NOT_FOUND

The channel specified does not exist.

MQRCCF_CHANNEL_IN_USE

The command did not specify a parameter or parameter value that was required.

MQRCCF_NO_STORAGE

Insufficient storage is available.

MQRCCF_COMMAND_FAILED

The command has failed.

MQRCCF_PORT_IN_USE

The port is in use.

MQRCCF_BIND_FAILED

The bind to a remote system during session negotiation has failed.

MQRCCF_SOCKET_ERROR

Socket error has occurred.

MQRCCF_HOST_NOT_AVAILABLE

An attempt to allocate a conversation to a remote system was unsuccessful. The error might be transitory, and the allocate might succeed later. This reason can occur if the listening program at the remote system is not running.