SVR5

putnextctl1(D3str)

putnextctl1 -- send a control message with a one byte parameter to a queue

Synopsis (Not in ODDI)

   #include <sys/stream.h>
   #include <sys/ddi.h>
   
   int putnextctl1(queue_t *q, int type, int param);

Description

putnextctl1 tests the type argument to make sure a data type has not been specified, and then attempts to allocate a message block. If successful, putnextctl calls the put(D2str) procedure of the queue pointed to by ``q->q_next'', passing it the allocated message with the one byte parameter specified by param.

Arguments

q: Pointer to the queue from which the message is to be sent.
type: Message type (must be a control type).
param: One byte parameter.

Return values

Upon successful completion, putnextctl1 returns 1. If type is a data type, or if a message block cannot be allocated, 0 is returned.

putnextctl1 fails if type is M_DATA(D7str), M_PROTO(D7str), or M_PCPROTO(D7str), or if a message block cannot be allocated.

Usage

In multithreaded DDI drivers, the q argument to putctl1(D3str) and putnextctl1 may not reference q_next (for example, an argument of q->q_next is erroneous in a multithreaded driver and is disallowed by the DDI). putnextctl1(q, type) is provided as a multiprocessor-safe equivalent to the common call putctl1(q->q_next, type), which is no longer allowed for DDI drivers.

Context

Base or Interrupt.

Synchronization constraints

Does not block.

Driver-defined basic locks, read/write locks, and sleep locks may not be held across calls to this function.

The caller cannot have the stream frozen [see freezestr(D3str)] when calling this function.

Hardware applicability

All

Version applicability

ddi: 3, 5, 5mp, 6, 6mp, 7, 7mp, 7.1, 7.1mp, 8, 8mp

References

put(D2str), put(D3str), putctl(D3str), putctl1(D3str), putnextctl(D3str)

Examples

See putnextctl(D3str) for an example of putnextctl1.