Guardian Procedure Calls Reference Manual

finishes with a call to FILE_AWAITIO64_ or FILE_COMPLETEL_ or is canceled by a call
to CANCEL or CANCELREQL.
◦ If the file is opened for nowait I/O, you must not modify the buffer before the I/O finishes
with a call to FILE_AWAITIO64_ or FILE_COMPLETEL_. This also applies to other processes
that might be sharing the segment. It is the application's responsibility to ensure this.
◦ If the file is opened for nowait I/O, a selectable extended data segment containing the
buffer need not be in use at the time of the call to FILE_AWAITIO64_ or FILE_COMPLETEL_.
◦ Nowait I/O initiated with this routine can be canceled with a call to CANCEL or
CANCELREQL. The I/O is canceled if the file is closed before the I/O finishes or
FILE_AWAITIO64_ is called with a positive time limit and specific file number, and the
request times out.
◦ A file opened by FILE_OPEN_ uses direct I/O transfers by default; you can use SETMODE
function 72 to force the system to use an intermediate buffer in the process file segment
(PFS) for I/O transfers. A file opened by OPEN uses a PFS buffer for I/O transfers, except
for large transfers to DP2 disks.
◦ If the extended address of the buffer is odd, bounds checking rounds the address to the
next lower word boundary and checks an extra byte as well. The odd address is used
for the transfer.
• See the FILE_LOCKREC64_ procedure Considerations (page 454).
• See the FILE_READUPDATE64_ procedure Considerations (page 488).
OSS Considerations
This procedure operates only on Guardian objects. If an OSS file is specified, error 2 is returned.
Related Programming Manuals
For programming information about the FILE_READUPDATELOCK64_ procedure, see the Enscribe
Programmer's Guide.
FILE_READUPDATELOCK64_ Procedure 495