NAME

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

STRUCTURE MEMBERS

ulong

so_flags;

/* options to set * /

short           so_readopt;      /* read option * /
ushort          so_wroff;        /* write offset * /
long            so_minpsz;       /* minimum read packet size * /
long            so_maxpsz;       /* maximum read packet size * /
ulong           so_hiwat;        /* read queue high water mark * /
ulong           so_lowat;        /* read queue low water mark * /
unsigned char   so_band;         /* band for water marks * /

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 min packet size

SO_MAXPSZ

set max 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/writes

SO_NDELOFF

STREAMS semantics for NDELAY reads/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 stream

SO_BAND

water marks affect band

When SO_READOPT is set, the so_readopt field of the stroptions sturcture can take one of the following values:

RNORM

read msg norm

RMSGD

read msg discard

RMSGN

read msg no discard

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

SEE ALSO

STREAMS Programmer's Guide