T-Kernel Specification (1.B0.02)

120 CHAPTER 4. T-KERNEL/OS FUNCTIONS
tk del mbf
Delete Message Buffer
[C Language Interface]
ER ercd = tk_del_mbf ( ID mbfid ) ;
[Parameters]
ID mbfid Message buffer ID
[Return Parameters]
ER ercd Error code
[Error Codes]
E OK
E ID
E NOEXS
Normal completion
Invalid ID number (mbfid is invalid or cannot be used)
Object does not exist (the message buffer designated in mbfid does not exist)
[Description]
Deletes the message buffer designated in mbfid.
Issuing this system call releases the corresponding message buffer and control block memory space, as
well as the message buffer space.
This system call completes normally even if there were tasks queued in the message buffer for message
receipt or message sending, but error code E DLT is returned to the tasks in WAIT state. If there are
messages left in the message buffer when it is deleted, the message buffer is deleted anyway. No error
code is returned and the messages are discarded.
Task A
(1)
tk snd mbf(mbfid)
Task B
(2)
tk rcv mbf(mbfid)
Message send wait (TTW SMBF) if wait entered at (1)
Message receive wait (TTW RMBF) if wait entered at (2)
Figure 4.4: Synchronous Communication Using Message Buffer of bufsz = 0
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T-Kernel 1.B0.02