OSI/AS Programming Manual

Appendix C Module File Management (MFM)
Procedure Calls
056783 Tandem Computers Incorporated C–1
This section contains detailed reference information for the two module file
management (MFM) procedure calls you can use with the APS procedures.
The external declarations for the current version of the MFM procedures are provided
in the system files $SYSTEM.SYSTEM.EXTDECS0 (TAL declarations) and
$SYSTEM.SYSTEM.CEXTDECS (C declarations). You must source in EXTDECS0 or
include CEXTDECS at the beginning of each program module that makes calls to these
procedures.
The APS procedures call the GUARDIAN 90 file-system procedures internally to
perform file-system I/O operations. The MFM_AWAITIOX_ procedure is needed to
complete file-system I/O operations performed by the APS procedures. The
MFM_AWAITIOX_ procedure completes pending operations both from calls to APS
procedures and from direct calls your programs make to the file-system procedures. If
any APS operations are outstanding, you cannot call AWAITIOX with a filenum of -1 to
get the first completion of an APS or file-system procedure; instead, you must call
MFM_AWAITIOX_.
The MFM_CANCELREQ_ procedure should be used to cancel a nowait operation
started by a previous APS procedure call.
If you are modifying an existing program that calls AWAITIOX, you can easily change
the AWAITIOX calls to MFM_AWAITIOX_ calls by altering the parameters to the
format specified in this appendix and sourcing in the declaration for
MFM_AWAITIOX_ from $SYSTEM.SYSTEM.EXTDECS. You can make similar
alterations to change CANCELREQ calls to MFM_CANCELREQ_ calls.
For more information about how to use these procedure calls, refer to “Nowait Mode”
in Section 2. For an explanation of the notation used in the syntax descriptions, see
Figure 3-1 in Section 3.
For information about the significance of condition codes, see the “Considerations” for
each of the two procedures in this appendix.