Guardian Procedure Calls Reference Manual

I/O operation completes with a call to the FILE_AWAITIO64_ or FILE_COMPLETEL_
procedure or the call is canceled by a call to CANCEL or CANCELREQL.
◦ If the file is opened for nowait I/O, the extended segment containing the buffers must be
in use at the time of the call to the AWAITIOX , FILE_AWAITIO64_, or FILE_COMPLETE[L]_
procedure.
◦ Nowait I/O initiated with these routines might be canceled with a call to CANCEL or
CANCELREQ[L]. The I/O operation is canceled if the file is closed before the I/O operation
completes or if the AWAITIOX, FILE_AWAITIO64_, or FILE_COMPLETE[L]_ procedure is
called with a positive time limit and the specific file number and the request times out.
◦ 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.
Example
In the following example, the WRITEBUFFER contains the information to be written, and READBUFFER
contains information that was read. In this case, 1 byte is to be written, and up to 72 bytes are to
be read. The NUM^READ indicates how many bytes are read into the READBUFFER.
ERROR := FILE_WRITEREAD64_( FILE^NUM, WRITEBUFFER, READBUFFER, 1, 72, NUM^READ );
FILE_WRITEREAD[64]_ Procedures 535