Guardian Procedure Calls Reference Manual

MESSAGESTATUS Procedure
Summary
Syntax for C Programmers
Syntax for TAL Programmers
Parameter
Returned Value
Considerations
Related Programming Manual
Summary
The MESSAGESTATUS procedure determines if a particular message received through READUPDATE
has been canceled.
Syntax for C Programmers
#include <cextdecs(MESSAGESTATUS)>
short MESSAGESTATUS ( [ short message-tag ] );
Syntax for TAL Programmers
status := MESSAGESTATUS ( [ message-tag ] ); ! i
Parameter
message-tag
input
INT:value
is the message tag returned from FILE_GETRECEIVEINFO_ or RECEIVEINFO following receipt
of the message. If omitted, the most recently received message is indicated.
Returned Value
INT
Cancellation status of the indicated message:
Message has been canceled.1
Message has not been canceled.0
No pending message is associated with the given tag (see Considerations).-1
Considerations
• If a message is canceled, any information supplied to REPLY (which must still be called) is not
passed back to the message originator. A message can be canceled because the originator
called CANCEL, CANCELREQ, FILE_CLOSE_, CLOSE, or certain forms of AWAITIO;
cancellation will also be caused by a stop of the originating process, failure of the originator's
processor, or a network communication failure.
• This procedure is best used for a program that is concerned about one particular request. If
a program deals with many requests concurrently and constantly monitors $RECEIVE, use of
system message -38 (queued message cancellation) may be more appropriate. You can be
828 Guardian Procedure Calls (M)