stroptions

- options structure for M_SETOPTS message

Synopsis

#include <sys/stream.h>
#include <sys/stropts.h>
#include <sys/ddi.h>
#include <sys/sunddi.h>

Interface Level

Architecture independent level 1 (DDI/DKI)

Description

The M_SETOPTS message contains a stroptions structure and is used to control options in the stream head.

Structure Members

uint_t           so_flags;      /* options to set */
short            so_readopt;    /* read option */
ushort_t         so_wroff;      /* write offset */
ssize_t          so_minpsz;     /* minimum read packet size */
ssize_t          so_maxpsz;     /* maximum read packet size */
size_t           so_hiwat;      /* read queue high water mark */
size_t           so_lowat;      /* read queue low water mark */
unsigned char    so_band;       /* band for water marks */
ushort_t         so_erropt;     /* error option */

The following are the flags that can be set in the so_flags bit mask in the stroptions structure. Note that multiple flags can be set.

SO_READOPT

Set read option.

SO_WROFF

Set write offset.

SO_MINPSZ

Set minimum packet size

SO_MAXPSZ

Set maximum packet size.

SO_HIWAT

Set high water mark.

SO_LOWAT

Set low water mark.

SO_MREADON

Set read notification ON.

SO_MREADOFF

Set read notification OFF.

SO_NDELON

Old TTY semantics for NDELAY reads and writes.

SO_NDELOFFSTREAMS

Semantics for NDELAY reads and writes.

SO_ISTTY

The stream is acting as a terminal.

SO_ISNTTY

The stream is not acting as a terminal.

SO_TOSTOP

Stop on background writes to this stream.

SO_TONSTOP

Do not stop on background writes to this stream.

SO_BAND

Water marks affect band.

SO_ERROPT

Set error option.

When SO_READOPT is set, the so_readopt field of the stroptions structure can take one of the following values. See read(2).

RNORM

Read message normal.

RMSGD

Read message discard.

RMSGN

Read message, no discard.

When SO_BAND is set, so_band determines to which band so_hiwat and so_lowat apply.

When SO_ERROPT is set, the so_erropt field of the stroptions structure can take a value that is either none or one of:

RERRNORM

Persistent read errors; default.

RERRNONPERSIST

Non-persistent read errors.

OR'ed with either none or one of:

WERRNORM

Persistent write errors; default.

WERRNONPERSIST

Non-persistent write errors.

See Also

read(2), streamio(7I)

STREAMS Programming Guide