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.