tt_message_user(library call) tt_message_user(library call)
NAMEtt_message_user — retrieve the user information associated with a mes‐
sage object
SYNOPSIS
#include <Tt/tt_c.h>
void *tt_message_user(
Tt_message m,
int key);
DESCRIPTION
The tt_message_user function retrieves the user information stored in
data cells associated with the specified message object.
The user data is part of the message object (that is, the storage buf‐
fer in the application); it is not a part of the actual message. The
application can, therefore, only retrieve user information that the
application placed in the message.
The m argument is the opaque handle for the message involved in this
operation. The key argument is the user data cell to be retrieved.
The user data cell must be unique for this message.
RETURN VALUE
Upon successful completion, the tt_message_user function returns the
data cell, a piece of arbitrary user data that can hold a void *. The
application can use tt_ptr_error(3) to extract one of the following
Tt_status values from the returned data:
TT_OK The operation completed successfully.
TT_ERR_NOMP
The ttsession(1) process is not running and the ToolTalk ser‐
vice cannot restart it.
TT_ERR_POINTER
The pointer passed does not point to an object of the correct
type for this operation.
APPLICATION USAGE
The application should use tt_free(3) to free any data stored in the
address returned by the ToolTalk API.
The user data cell is intended to hold an address. If the address
selected is equal to one of the Tt_status enumerated values, the result
of the tt_ptr_error(3) function will not be reliable.
SEE ALSO
Tt/tt_c.h - Tttt_c(5), tt_ptr_error(3), tt_free(3).
tt_message_user(library call)
