ToolTalk User's Guide

Defining Dynamic Messages

To create and register a dynamic message pattern, you allocate a new pattern object, fill in the proper information, and register it. When you are done with the pattern (that is, when you are no longer interested in messages that match it), either unregister or destroy the pattern. You can register and unregister dynamic message patterns as needed.

The ToolTalk functions used to create, register, and unregister dynamic message patterns are listed in Table 9–1.

Table 9–1 Functions for Creating, Updating, and Deleting Message Patterns

ToolTalk Function 



Create Pattern 

tt_pattern_arg_add(Tt_pattern p, Tt_mode n, const char *vtype, const char *value)

Add string arguments 

tt_pattern_barg_add(Tt_pattern m, Tt_mode n, const char *vtype, const unsigned char *value, int len)

Add byte array arguments 

tt_pattern_iarg_add(Tt_pattern m, Tt_mode n, const char *vtype, int value)

Add integer arguments 

tt_pattern_xarg_add(Tt_pattern m, Tt_mode n, const char *vtype, xdrproc_t xdr_proc, void *value)

Adds an xdr argument to a byte array 

tt_pattern_bcontext_add(Tt_pattern p, const char *slotname, const unsigned char *value, int length);

Add byte array contexts 

tt_pattern_context_add(Tt_pattern p, const char *slotname, const char *value);

Add string contexts 

tt_pattern_icontext_add(Tt_pattern p, const char *slotname, int value);

Add integer contexts 

tt_pattern_address_add(Tt_pattern p, Tt_address d)

Add address 

tt_pattern_callback_add(Tt_pattern p, Tt__message_callback_action f)

Add message callback 

tt_pattern_category_set(Tt_pattern p, Tt_category c)

Set category 

tt_pattern_class_add(Tt_pattern p, Tt_class c)

Add class 

tt_pattern_disposition_add(Tt_pattern p, Tt_disposition r)

Add disposition 

tt_pattern_file_add(Tt_pattern p, const char *file)

Add file 

tt_pattern_object_add(Tt_pattern p, const char *objid)

Add object 

tt_pattern_op_add(Tt_pattern p, const char *opname)

Add operation 

tt_pattern_opnum_add(Tt_pattern p, int opnum)

Add operation number 

tt_pattern_otype_add(Tt_pattern p, const char *otype)

Add object type 

tt_pattern_scope_add(Tt_pattern p, Tt_scope s)

Ad scope 

tt_pattern_sender_add(Tt_pattern p, const char *procid)

Add sending process identifier 

tt_pattern_sender_ptype_add(Tt_pattern p, const char *ptid)

Add sending process type 

tt_pattern_session_add(Tt_pattern p, const char *sessid)

Add session identifier 

tt_pattern_state_add(Tt_pattern p, Tt_state s)

Add state 

tt_pattern_user_set(Tt_pattern p, int key, void *v)

Set user 

tt_pattern_register(Tt_pattern p)

Register pattern 

tt_pattern_unregister(Tt_pattern p)

Unregister pattern 

tt_pattern_destroy(Tt_pattern p)

Destroy message pattern 

Note –

The return type for all functions except tt_pattern_create is Tt_status; tt_pattern_create returns Tt_pattern.

Creating a Message Pattern

To create message patterns, use the tt_pattern_create function. You can use this function to get a handle or opaque pointer to a new pattern object, and then use this handle on succeeding calls to reference the pattern.

To fill in pattern information, use the tt_pattern_attribute_add and tt_pattern_attribute_set calls. You can supply multiple values for each attribute you add to a pattern. The pattern attribute matches a message attribute if any of the values in the pattern match the value in the message. If no value is specified for an attribute, the ToolTalk service assumes that you want any value to match. Some attributes are set and, therefore, can only have one value.

Adding a Message Pattern Callback

To add a callback routine to your pattern, use the tt_pattern_callback_add function.

Note –

Callbacks are called in reverse order of registration (for example, the most recently added callback is called first).

When the ToolTalk service matches a message, it automatically calls your callback routine to examine the message and take appropriate actions. When a message that matches a pattern with a callback is delivered to you, it is processed through the callback routine. When the routine is finished, it returns TT_CALLBACK_PROCESSED and the API objects involved in the operation are freed. You can then use tt_message_destroy to destroy the message, which frees the storage used by the message, as illustrated in the following code sample.

sample_msg_callback(Tt_message m, Tt_pattern p)
	... process the reply msg ...


Registering a Message Pattern

To register the completed pattern, use the tt_pattern_register() function. After you register your pattern, you join the sessions or files of interest.

The following code sample creates and registers a pattern.

	 * Create and register a pattern so ToolTalk 
 * knows we are interested
	 * in “ttsample1_value” messages within 
 * the session we join.

	pat = tt_pattern_create();
	tt_pattern_category_set(pat, TT_OBSERVE);
	tt_pattern_scope_add(pat, TT_SESSION);
	tt_pattern_op_add(pat, “ttsample1_value”);

Deleting and Unregistering a Message Pattern

Note –

If delivered messages that matched the deleted pattern have not been retrieved by your application (for example, the messages might be queued), the ToolTalk service does not destroy these messages.

To delete a message pattern, use the tt_pattern_destroy() function. This function first unregisters the pattern and then destroys the pattern object.

To stop receiving messages that match a message pattern without destroying the pattern object, use the tt_pattern_unregister() to unregister the pattern.

The ToolTalk service will automatically unregister and destroy all message pattern objects when you call tt_close.