ToolTalk User's Guide

Examining Messages

When your process receives a message, you examine the message and take appropriate action.

Before you start to retrieve values, obtain a mark on the ToolTalk API stack so that you can release the information the ToolTalk service returns to you all at once. Example 11-3 allocates storage, examines message contents, and releases the storage.

Example 11-3 Allocating, Examining, and Releasing Storage

        /*
         * Get a storage mark so we can easily free all the data
         * ToolTalk returns to us.
         */

        mark = tt_mark();

        if (0==strcmp("ttsample1_value", tt_message_op(msg_in))) {
                tt_message_arg_ival(msg_in, 0, &val_in);
                xv_set(gauge, PANEL_VALUE, val_in, NULL);
        }

        tt_message_destroy(msg_in);
        tt_release(mark);
        return;

Table 11-1 lists the ToolTalk functions you use to examine the attributes of a message you have received.

Table 11-1 Functions to Examine Message Attributes


Return Type	ToolTalk Function	Description
`Tt_address`	`tt_message_address(Tt_message m)`	The address of the message.
`Tt_status`	`tt_message_arg_bval(Tt_message m, int n, unsigned char *value, int len)`	The argument value as a byte array.
`Tt_status`	`tt_message_arg_ival(Tt_message m, int n, int *value)`	The argument value as an integer.
`Tt_status`	`tt_message_arg_xval(Tt_message m, int n, xdrproc_t xdr_proc, void *value)`	The argument value as an xdr.
`Tt_mode`	`tt_message_arg_mode(Tt_message m, int n)`	The argument mode (in, out, inout).
`char *`	`tt_message_arg_type(Tt_message m, int n)`	The argument type.
`char *`	`tt_message_arg_val(Tt_message m, int n)`	The argument value as a string.
`int`	`tt_message_args_count(Tt_message m)`	The number of arguments.
`Tt_class`	`tt_message_class(Tt_message m)`	The type of message (notice or request).
`int`	`tt_message_contexts_count(Tt_message m);`	The number of contexts.
`char *`	`tt_message_context_slotname(Tt_message m, int n);`	The name of a message's nth context.
`Tt_disposition`	`tt_message_disposition(Tt_message m)`	How to handle the message if there is no receiving application running.
`char *`	`tt_message_file(Tt_message m)`	The name of the file to which the message is scoped.
`gid_t`	`tt_message_gid(Tt_message m)`	The group identifier of the sending application.
`char *`	`tt_message_handler(Tt_message m)`	The procid of the handler.
`char *`	`tt_message_handler_ptype(Tt_message m)`	The ptype of the handler.
`char *`	`tt_message_object(Tt_message m)`	The object to which the message was sent.
`char *`	`tt_message_op(Tt_message m)`	The operation name.
`int`	`tt_message_opnum(Tt_message m)`	The operation number.
`char *`	`tt_message_otype(Tt_message m)`	The object type to which the message was sent.
`Tt_pattern`	`tt_message_pattern(Tt_message m)`	The pattern to which the message is to be matched.
`Tt_scope`	`tt_message_scope(Tt_message m)`	Who is to receive the message (FILE, SESSION, BOTH)
`char *`	`tt_message_sender(Tt_message m)`	The procid of the sending application.
`char *`	`tt_message_sender_ptype(Tt_message m)`	The ptype of the sending application.
`char *`	`tt_message_session(Tt_message m)`	The session from which the message was sent.
`Tt_state`	`tt_message_state(Tt_message m)`	The current state of the message.
`int`	`tt_message_status(Tt_message m)`	The current status of the message.
`char *`	`tt_message_status_string(Tt_message m)`	Text describing the current status of the message.
`uid_t`	`tt_message_uid(Tt_message m)`	The user identifier of the sending application.
`void *`	`tt_message_user(Tt_message m, int key)`	Opaque data internal to the application.