Guardian Procedure Calls Reference Manual

process file segment (PFS—also known as system buffers) 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.
Errors for READUPDATEX and READUPDATEXL
In addition to the errors currently returned from READUPDATE, error 22 is returned from
READUPDATEX and READUPDATEXL when:
• The address of a parameter is extended, but either the extended data segment is invalid or
the address is for a selectable segment that is not in use at the time of the call.
• The address of a parameter is extended, but it is an absolute address and the caller is not
privileged.
Related Programming Manuals
For programming information about the READUPDATE[X] procedure, see the Guardian Programmer's
Guide and the Enscribe Programmer's Guide.
1220 Guardian Procedure Calls (R)