MPE/iX Intrinsics Reference Manual (32650-90875)

378 Chapter7
Command Definitions (HP32208-HPLOACNMPROC)
HPFOPEN
process is already accessing this file when an
HPFOPEN/FOPEN call is issued with exclusive access
specified, an error status is returned to the process. If
another HPFOPEN/FOPEN call is issued for this file while
exclusive access is in effect, an error code is returned to
the process that issued that HPFOPEN/FOPEN call. Request
exclusive access only if the lock access mode is allowed by
the security provisions for the file. For message files,
specifying this value means that there can be only one
reader and one writer.
Exclusive access cannot be used with directories.
2 Read-Share access (semi-exclusive access). After the file is
opened, concurrent write access to this file through
another HPFOPEN/FOPEN request is prohibited, whether
issued by this process or another process, until this
process issues the FCLOSE request or terminates. A
subsequent request for the read/write or update
itemnum =11 obtains read access. However, other types of
read access are allowed. If a process already has write
access to the file when this HPFOPEN call is issued, an
error code is returned to the calling process. If another
HPFOPEN/FOPEN call that violates the read-only
restriction is issued while read-share access is in effect,
that call fails and an error code is returned to the calling
process. You can request read-share access only if you are
allowed the lock access mode by the security provisions for
the file. For message files, specifying this value means that
there can be multiple readers, but only one writer.
3 Share access. After the file is opened, this permits
concurrent access to this file by any process, in any access
mode, subject to other basic security provisions in effect.
For message files, specifying this value means that there
can be multiple writers and one reader.
Default: 0
(ASC) This option is ignored for devices.
FIFO files should be opened for Share Access (3). Other exclusive accesses
to file will cause unexpected results to occur.
14/I32 Multiaccess:
Passes a value indicating how the file's record pointer is to be shared. This
option is useful for sharing standard input devices where there is some
natural sequence of access to the file. This option permits processes located
in different jobs or sessions to open the same file and share that file's
record pointer.
The following values are valid: