MQ_TRANSPORT_EXIT - Transport retry exit

This call definition is provided solely to describe the parameters that are passed to the transport retry exit called by the message channel agent (MCA). No entry point called  MQ_TRANSPORT_EXIT  is actually provided by the MCA; the name  MQ_TRANSPORT_EXIT  is of no special significance because the name of the transport retry exit is provided by the queue-manager's configuration file.

This exit is supported in the following environments: AIX.

Syntax

Parameters

The  MQ_TRANSPORT_EXIT  call has the following parameters.

ExitParms (MQTXP) - input/output

Exit parameter block.

This structure contains information relating to the invocation of the exit. The exit sets information in this structure to indicate how processing should continue.

DestAddressLength (MQLONG) - input

Length in bytes of destination IP address.

This is the length of the destination IP address DestAddress. The value is always greater than zero.

DestAddress (MQCHAR×DestAddressLength) - input

Destination IP address.

This is the IP address of the destination. Its length is given by the DestAddressLength parameter.

Usage notes

1. The function performed by the exit is defined by the provider of the exit. The exit, however, must conform to the rules defined in the associated control block MQTXP.
2. The transport retry exit allows a channel to be paused based on criteria that are external to WebSphere MQ.

   If configured, the exit is called before each attempt to resend a failing data packet. When called, the exit can wait based on some external criterion, and not return control to the MCA until the exit decides that the resend of the data packet is likely to succeed. If the exit decides that transmission should be discontinued, the exit can instruct the MCA to close the channel.

C invocation

exitname (&ExitParms, DestAddressLength, DestAddress);

The parameters passed to the exit are declared as follows:

MQTXP   ExitParms;          /* Exit parameter block */
MQLONG  DestAddressLength;  /* Length in bytes of destination IP
                               address */
MQCHAR  DestAddress[n];     /* Destination IP address */