| Navigation: Language Reference > 13 - Built-in Functions >====== NOTIFICATION (receive information from sender thread) ====== |    |
NOTIFICATION(notifycode, <;thread>, <;parameter> )
| NOTIFICATION | Receives information from a sender thread. |
| notifycode | An UNSIGNED variable that receives a notify code value passed by the sender with a NOTIFY statement. |
| thread | An optional SIGNED variable that receives the number of the sender's thread parameter. |
| parameter | A LONG variable that receives the parameter passed by the sender with a NOTIFY statement. |
The NOTIFICATION function is used by a receiving thread. It receives the notification code, thread number, and parameter passed by the sending thread's NOTIFY statement.
NOTIFICATION returns FALSE (0) if the EVENT() function returns an event other than EVENT:Notify. If EVENT:Notify is posted, NOTIFICATION returns TRUE. Because calls to NOTIFY and NOTIFICATION are asynchronous, the sender thread can be closed already when receiver thread accepts the EVENT:Notify event.
NOTIFY and NOTIFICATION are a functional replacement for the SETTARGET(,thread) statement. They can also be used for safe transfer information between threads.
The code between SETTARGET(,thread) and a subsequent SETTARGET is executing in the context of the specified thread but also as a part of the current thread. Hence, two threads can execute the code in the same context. Also, related DLLs can associate their thread dependent data with the Thread ID of the current thread. These aspects make using SETTARGET(,thread) potentially dangerous in the new threading model.
The purpose of NOTIFY and NOTIFICATION is to provide a way to send a notification with parameters from one thread to another. The receiver thread can then execute the request in the correct context.
Return Data Type: BYTE
Example:
CASE EVENT()
OF EVENT:Accepted
CASE ACCEPTED()
OF ?Start
START (T1)
OF ?Load
CALL ('DLL.DLL', 'EntryPoint', 1)
ELSE
Q.Feq = ACCEPTED()
GET (Q, Q.Feq)
IF ERRORCODE() = 0 AND Q.Op <;> 0
DM &= Q.ID + 0
DM.ExecuteMenu (Q.Op)
END
END
OF EVENT:Notify
IF NOTIFICATION (NCode,, NParam) !NOTIFY has sent a Notify Event. Get Code and Parameter
DM &= NParam + 0 !Assign passed parameter to reference var
CASE Ncode !Test the Notify Code
OF NOTIFY:Load
DM.CreateMenu (Q) !Execute appropriate action
OF NOTIFY:Unload
DO DestroyMenu
UNLOAD ('DLL.DLL') !Execute appropriate action
END
END
END
See Also: