IO_GET_TERM_REASON(3I) — HP-UX

NAME

io_get_term_reason − determine how last read terminated

SYNOPSIS

int io_get_term_reason (eid);
int eid;

DESCRIPTION

Io_get_term_reason returns the termination reason for the last read made on this entity id. Eid is an entity identifier of an open HP-IB raw bus or GPIO device file obtained from an open(2), dup(2), fcntl(2), or creat(2) call.

All entity ids descending from an open(2) request (such as from dup(2) or fork(2)) set this status. For example, if the calling process had opened this entity id, and later forked, the status returned would be from the last read done by either the calling process or its child.

RETURN VALUE

Io_get_term_reason returns a value indicating how the last read on the specified entity id was terminated. This value is interpreted as follows (note that combinations are possible):

Value	Description
−1	An error was encountered while making
	this function request.
0	Last read encountered some abnormal termination
	reason not covered by any of the other reasons.
1	Last read terminated by reading the number of bytes
	requested.
2	Last read terminated by detecting the specified
	termination character.
4	Last read terminated by detecting some device-imposed
	termination condition. Examples are: EOI for
	HP-IB, PSTS line on GPIO, or
	some other end-of-record condition, such as the physical
	end-of-record mark on a 9-track tape.

ERRORS

Io_get_term_reason fails under the following circumstances, and sets errno (see errno(2)) to the value in square brackets:

[EBADF] eid does not refer to an open file.

[ENOTTY] eid does not refer to a channel device file.

DEPENDENCIES

Series 300
For the GPIO interface, PSTS is checked only at the beginning of a transfer. An interrupt caused by an EIR will also terminate a transfer. The value of the termination reason in this case is also 4.

Series 500
If the last read had multiple applicable termination reasons, such as having EOI asserted on the last byte when that byte was the termination match character (see io_eol_ctl(3I)), the highest numbered reason is used (in this case, 4). Since interactive terminals are treated as record-oriented devices when they are in cooked mode, the termination reason is 4 when terminated by a new-line character. If no read has been done on the entity id since it was opened, the value of the termination reason is 0.

The GPIO interface does not support this function.

AUTHOR

Io_get_term_reason was developed by HP.

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