STREAMS/UX for the HP 9000 Reference Manual

Differences Between STREAMS/UX and System V Release 4 STREAMS

HP-UX Modiﬁcations to STREAMS/UX Utilities

the put routine of the speciﬁed queue. putctl2 returns 0 if the type is

M_DATA, M_PROTO or M_PCPROTO, or if a message block cannot be

allocated. putctl2 returns 1 if it completes successfully.

putnextctl2

STREAMS/UX provides the additional utility putnextctl2. This utility can

be used to send a control message with a two-byte parameter to the next

queue in a stream. For example, putnextctl2 can send the new style of an

M_ERROR message, which is two bytes long, to the next queue in a stream.

int putnextctl2(q, type, p1, p2);

queue_t * q;

int type;

int p1;

int p2;

The q parameter is the queue from which the message is sent. The message

is sent to q->q_next. The type parameter is the message type. The p1 and

p2 parameters are the two bytes of data in the message. The putnextctl2

utility ensures that the type is not a data type. The utility also allocates a

message block, ﬁlls in the data, and calls the put routine of q->q_next.

putnextctl2 returns 0 if the type is M_DATA, M_PROTO, or M_PCPROTO,

or if a message block cannot be allocated. putnextctl2 returns 1 if it

completes successfully.

qprocson and qprocsoff

SVR4 MP STREAMS/UX provides qprocson and qprocsoff, which on a

multiprocessor system allows a module's put and service routines to run

concurrently with open and close. STREAMS/UX does not allow this much

parallelism. A module's or driver's put and service routines cannot run at the

same time as the open or close. Although STREAMS/UX does not run the

put or service routine in parallel with the open or close, it does queue any

requests to run the put or service routine. STREAMS/UX will process these

when open ﬁnishes. Also, if open or close sleeps, STREAMS/UX can run

the put and service routines while open or close are sleeping. However, a

put or service routine cannot do the wakeup on a sleeping open or close.

STREAMS/UX provides stubs which are no-ops for qprocson and qprocsoff

to make porting easier.