tt_pattern_callback_add(3) ToolTalk Functions tt_pattern_callback_add(3)NAMEtt_pattern_callback_add - register a message-matching callback function
SYNOPSIS
#include <Tt/tt_c.h>
Tt_status tt_pattern_callback_add(Tt_pattern m,
Tt_message_callback f);
DESCRIPTION
The tt_pattern_callback_add() function registers a callback function
that will be automatically invoked by tt_message_receive(3) whenever a
message matches the pattern.
The callback is defined in <Tt/tt_c.h>. If the callback returns
TT_CALLBACK_CONTINUE, other callbacks will be run; if no callback
returns TT_CALLBACK_PROCESSED, tt_message_receive(3) returns the mes‐
sage. If the callback returns TT_CALLBACK_PROCESSED, no further call‐
backs will be invoked for this event; tt_message_receive(3) does not
return the message.
The m argument is the opaque handle for the pattern involved in this
operation.
The f argument is the message callback to be run.
The application should check the tt_message_uid(3) and tt_mes‐
sage_gid(3) against the User ID and Group ID of the application receiv‐
ing the messsage. If the UID and/or GID of the application do not match
that of the message then the receiving application should consider
failing the message with TT_DESKTOP_EACCES.
RETURN VALUE
Upon successful completion, the tt_pattern_callback_add() function
returns the status of the operation as one of the following Tt_status
values:
TT_OK The operation completed successfully.
TT_ERR_NOMP
The ttsession(1) process is not running and the ToolTalk
service cannot restart it.
TT_ERR_POINTER
The pointer passed does not point to an object of the cor‐
rect type for this operation.
SEE ALSOtt_c(5), tt_pattern_register(3), tt_message_receive(3).
ToolTalk 1.3 1 March 1996 tt_pattern_callback_add(3)
