Open System Services System Calls Reference Manual (G06.29+, H06.08+, J06.03+)

SPT_CONTROL(2) OSS System Calls Reference Manual
The following considerations apply to use on magnetic tapes:
When device is not ready
If a magnetic tape rewind is performed concurrently with application program
execution (that is, a rewind operation other than 6), any attempt to perform a
read, write, or control operation to the rewinding tape unit while rewind is taking
place results in an error indication. A subsequent call to the FILE_GETINFO_
or FILEINFO procedure shows that an error 100 occurred.
Wait for rewind to complete
If a magnetic tape rewind operation of 6 (wait for completion) is performed as a
nowait operation, the application waits at the call to the AWAITIO procedure for
the rewind to complete.
The following considerations apply to use for interprocess communication:
Nonstandard operation and param values
You can specify any value for the operation and param parameters. An
application-defined protocol should be established for interpreting nonstandard
parameter values.
Process not accepting system messages
If the object of the control operation is not accepting process CONTROL mes-
sages, the call to SPT_CONTROL() completes but a subsequent call to the
FILE_GETINFO_ or FILEINFO procedure shows that an error 7 occurred.
Process control You can obtain the process identifier of the caller to SPT_CONTROL() in a
subsequent call to the FILE_GETRECEIVEINFO_ (or LASTRECEIVE or
RECEIVEINFO) procedure.
RETURN VALUES
The SPT_CONTROL() function returns 0 (zero) upon successful completion. Otherwise, this
function returns a nonzero Guardian file-system error number that indicates the outcome of the
operation.
When device handlers do not allow the operation, Guardian file-system error 2 is returned. For
information about Guardian file-system error numbers, see the Guardian Procedure Errors and
Messages Manual.
ERRORS
None. This function does not set the errno variable.
RELATED INFORMATION
Functions: SPT_CANCEL(2), SPT_FILE_CLOSE_(2), SPT_FILE_OPEN_(2),
SPT_LOCKFILE(2), SPT_LOCKREC(2), SPT_READLOCKX(2),
SPT_READUPDATELOCKX(2), SPT_READUPDATEX(2), SPT_READX(2),
SPT_SETMODE(2), SPT_UNLOCKFILE(2), SPT_UNLOCKREC(2),
SPT_WRITEREADX(2), SPT_WRITEUPDATEUNLOCKX(2),
SPT_WRITEUPDATEX(2), SPT_WRITEX(2).
STANDARDS CONFORMANCE
This function is an extension to the UNIX 98 specification. Interfaces documented on this refer-
ence page conform to the following industry standards:
• IEEE Std 1003.1c-1995, POSIX System Application Program Interface
The use of the header file spthread.h is an HP exception to the POSIX standard.
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