IBM MQ API exit context structure (MQAXC)

The MQAXC structure, an external control block, is used as an input parameter to an API exit.

MQAXC has the following C declaration:

typedef struct tagMQAXC {
   MQCHAR4   StrucId;                /* Structure identifier */
   MQLONG    Version;                /* Structure version number */
   MQLONG    Environment;            /* Environment */
   MQCHAR12  UserId;                 /* UserId associated with appl */
   MQBYTE40  SecurityId              /* Extension to UserId running appl */
   MQCHAR264 ConnectionName;         /* Connection name */
   MQLONG    LongMCAUserIdLength;    /* long MCA user identifier length */
   MQLONG    LongRemoteUserIdLength; /* long remote user identifier length */
   MQPTR     LongMCAUserIdPtr;       /* long MCA user identifier address */
   MQPTR     LongRemoteUserIdPtr;    /* long remote user identifier address */
   MQCHAR28  ApplName;               /* Application name */
   MQLONG    ApplType;               /* Application type */
   MQPID     ProcessId;              /* Process identifier */
   MQTID     ThreadId;               /* Thread identifier */

   /* Ver:1 */
   MQCHAR    ChannelName[20]         /* Channel Name */
   MQBYTE4   Reserved1;              /* Reserved */
   PMQCD     pChannelDefinition;     /* Channel Definition pointer */ 
 };

The parameters to MQAXC are:

StrucId (MQCHAR4) - input

The exit context structure identifier, with a value of MQAXC_STRUC_ID. For C programs, the constant MQAXC_STRUC_ID_ARRAY is also defined, with the same value as MQAXC_STRUC_ID, but as an array of characters instead of a string.

The exit handler sets this field on entry to each exit function.

Version (MQLONG) - input

The structure version number, with a value of:

MQAXC_VERSION_2: Version number for the exit context structure.
MQAXC_CURRENT_VERSION: Current version number for the exit context structure.

The exit handler sets this field on entry to each exit function.

Environment (MQLONG) - input

The environment from which an IBM MQ API call was issued that resulted in an exit function being driven. Valid values for this field are:

MQXE_OTHER: This value is consistent with invocations an API exit sees if the exit is called from a server application. This means that an API exit runs unchanged on a client and does not see anything different.
If the exit really needs to determine whether it is running on the client, the exit can do so by looking at the ChannelName and ChannelDefinition fields.
MQXE_MCA: Message channel agent
MQXE_MCA_SVRCONN: A message channel agent acting on behalf of a client
MQXE_COMMAND_SERVER: The command server
MQXE_MQSC: The runmqsc command interpreter

The exit handler sets this field on entry to each exit function.

UserId (MQCHAR12) - input

The user ID associated with the application. In particular, in the case of client connections, this field contains the user ID of the adopted user as opposed to the user ID under which the channel code is running. If a blank user ID flows from the client, then no change is made to the user ID already being used. That is, no new user ID is adopted.

The exit handler sets this field on entry to each exit function. The length of this field is given by MQ_USER_ID_LENGTH.

In the case of a client, this is the user ID sent from the client to the server. Note, that this might not be the effective user ID the client is running against in the queue manager, as there could be an MCAUser or CHLAUTH configuration which changes the user ID.

SecurityId (MQBYTE40) - input

An extension to the user ID running the application. Its length is given by MQ_SECURITY_ID_LENGTH.

ConnectionName (MQCHAR264) - input

The connection name field, set to the address of the client. For example, for TCP/IP, it would be the client IP address.

The length of this field is given by MQ_CONN_NAME_LENGTH.

In the case of a client, this is the partner address of the queue manager.

LongMCAUserIdLength (MQLONG) - input

The length of the long MCA user identifier.

When MCA connects to the queue manager this field is set to the length of the long MCA user identifier (or zero if there is no such identifier).

In the case of a client, this is the client long user identifier.

LongRemoteUserIdLength (MQLONG) - input

The length of the long remote user identifier.

When MCA connects to the queue manager this field is set to the length of the long remote user identifier. Otherwise this field will be set to zero

In the case of a client, set this field to zero.

LongMCAUserIdPtr (MQPTR) - input

Address of long MCA user identifier.

When MCA connects to the queue manager this field is set to the address of the long MCA user identifier (or to a null pointer if there is no such identifier).

In the case of a client, this is the client long user identifier.

LongRemoteUserIdPtr (MQPTR) - input

The address of the long remote user identifier.

When MCA connects to the queue manager this field is set to the address of the long remote user identifier (or to a null pointer if there is no such identifier).

In the case of a client, set this field to zero.

ApplName (MQCHAR28) - input

The name of the application or component that issued the IBM MQ API call.

The rules for generating the ApplName are the same as for generating the default name for an MQPUT.

The value of this field is found by querying the operating system for the program name. Its length is given by MQ_APPL_NAME_LENGTH.

ApplType (MQLONG) - input

The type of application or component that issued the IBM MQ API call.

The value is MQAT_DEFAULT for the platform on which the application is compiled, or it equates to one of the defined MQAT_* values.

The exit handler sets this field on entry to each exit function.

ProcessId (MQPID) - input

The operating system process identifier.

Where applicable, the exit handler sets this field on entry to each exit function.

ThreadId (MQTID) - input

The MQ thread identifier. This is the same identifier used in MQ trace and FFST dumps, but might be different from the operating system thread identifier.

Where applicable, the exit handler sets this field on entry to each exit function.

ChannelName (MQCHAR) - input

The name of the channel, padded with blanks, if applicable and known.

If not applicable, this field is set to NULL characters.

Reserved1 (MQBYTE4) - input

This field is reserved.

ChanneDefinition (PMQCD) - input

A pointer to the channel definition being used, if applicable and known.

If not applicable, this field is set to NULL characters.

Note that the pointer is only completed if the connection is processing on behalf of an IBM MQ channel and that channel definition has been read.

In particular, the channel definition is not given on the server when the first MQCONN call is made for the channel. Furthermore, if the pointer is filled, the structure (and any sub structures) pointed to by the pointer must be treated as read only; any updating of the structure would lead to unpredictable results and is not supported.

In the case of a client, fields other than those with a value specified for a client, contain values that are appropriate for a client application.