MPE/iX Intrinsics Reference Manual (32650-90875)

Chapter 5 125
Command Definitions (FCONTROL - FLOCK)
FCONTROL
the FWRITE intrinsic for these directives.)
If
item passes either the prespacing (%101 or %401) or postspacing (%100
or %400) carriage control directives, one of the following values is returned
in
item , indicating the setting of the device prior to the FCONTROL call:
0 Postspacing
1 Prespacing
If both a mode control directive and a carriage control directive need to be
specified, an additional call to FWRITE or FCONTROL must be made.
This
itemnum is ignored for byte stream files. It is not applicable to
directories since applications are not permitted to write to directory files.
Default: postspacing with automatic page eject (except for
FORTRAN77/XL and COBOLII/XL: prespacing with automatic page
eject).
2/I16 Complete I/O:
Ensures that requested I/O has been physically completed. Valid only for
buffered files. Posts the block being written (full or not). Ignored for
message files.
Item is ignored.
This
itemnum is supported for byte stream files. It is not applicable to
directories since applications are not permitted to write to directory files.
(KSAM) A checkpoint record is written. In the event of a system crash,
recovery would be done to this state of the files.
3/U16 Device status:
Returns a record containing information about the state of the device
associated with the file immediately after the last I/O operation (including
HPFOPEN/FOPEN) on the file. The record size and contents are
device-dependent.
4/U16 Set read timeout interval:
Passes the timeout interval, in seconds, to be applied to the next read from
the specified file. The maximum value allowed is 65,535 seconds. If input is
requested from a file but is not received in this interval, the FREAD request
terminates with CCL (1). The interval is specified in seconds and returned
no value. If this interval is zero, any previously established interval is
cancelled, and no timeout occurs.
If a timeout value is being set for a read posted against a device connected
through a PAD, add enough time to compensate for time delays that may
be caused by the network.
A timeout value should be used for programs reading from an unattended
device to prevent "hangs". Timeouts can be used to terminate binary reads
(only as a safeguard to prevent a program from waiting forever for a read
to complete).