Hitachi FL.NET, User Manual

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5 USER GUIDE
5-53
(3) C mode handler or mathematical/logical function
(a) Message transmission request by C mode handler
A C mode handler is called as a C function. It issues a message request to the FL.NET
module to exchange data in place of a user program. Various C mode handlers are
available for use with all message types.
A C mode handler must be called by specifying its entry address. A user program cannot be
created (linked) in such a manner that a C mode handler is contained in it.
User application
program
Linkage provided
by a user program
only
wordrd( )
wordwt( )
comoffset( )
C mode handler (main)
wordrd( )
wordwt( )
comoffset( )
C mode handler (sub)
It should also be pointed out in this connection that the C mode handler for the FL.NET
module merely issues a request to the FL.NET module and then terminates its whole process
immediately.
When the return code fed from the C mode handler is -1 (0xFFFFFFFF), it means that a
parameter abnormality exists or that the handler is busy processing another message.
Check the data at an error code storage address specified at C mode handler startup. When
the return code is 0, the C mode handler indicates that a request has been processed
normally.
When return code is -2 (0xFFFFFFFE) during S10V mounting, it means that an address on
CMU was specified at parameter which specifies an address, such as an error code storage
address.
After receipt of a request, the FL.NET module turns ON (sets) the “user request processing
in progress” bit in the self-node status flag, and turns it OFF (resets it) at the end of the
processing.
To verify the end of message processing after issuance, check the self-node status flag. The
status indicates the end of the processing.