Asynchronous Serial Communications Programmer's Reference Manual (32022-90052)

158 Chapter8
Intrinsics Reference
FCHECK
blocknum 32-bit signed integer by reference
(optional)
For asynchronous devices, this parameter is used to
return the number of records read or written to a device
since the last FOPEN. A logical record count is
returned for spoolfiles; a physical record count is
returned for fixed and undefined record files.
numrecs 16-bit signed integer by reference
(optional)
Returns the number of logical records in the block
(blocking factor). Blocking factor is not meaningful for
asynchronous devices.
Default: The number of logical records is not returned.
Summary of Error Codes
Table 8-2 lists the file system error codes that you are most likely to
encounter during intrinsic calls related to asynchronous devices.
Table 8-2 Error Codes
FS Code
(decimal)
Description
0 Successful (no errors) or end-of-file (EOF) reached.
20 Invalid operation requested by program (for example, you tried to set the terminal
type to -24, which is an invalid entry).
21 Parity error occurred during read.
22 Read limit timer set by user expired. (Timer set via FCONTROL(4).)
24 Device not ready (not on line, modem’s Data Set Ready signal not “high”, or line
disconnected).
27 Block mode read timer expired. This timer is set by the system, and is not user
changeable. If no RS character is received before the time expires, the read is
terminated.
28 Timing error—Data arrived at controller faster than it could be serviced (data
overrun).
31 Read ended by an Additional End-of-Record character (defined via
FCONTROL(25)).
32 Software abort of I/O operation occurred (for example, an ABORTIO command was
entered.
33 Data was lost, or no buffer was available.
42 Operation inconsistent with device type (for example, attempted to set an invalid
line speed via FCONTRO(11)).