PUTNEXTCTL1(9F) Kernel Functions for Drivers PUTNEXTCTL1(9F)
NAME
putnextctl1 - send a control message with a one-byte parameter to a
queue
SYNOPSIS
#include <sys/stream.h>
int putnextctl1(
queue_t *q,
int type,
int p);
INTERFACE LEVEL
Architecture independent level 1 (DDI/DKI).
PARAMETERS
q Queue to which the message is to be sent.
type Type of message.
p One-byte parameter.
DESCRIPTION
The
putnextctl1() function, like
putctl1(9F), tests the
type argument
to make sure a data type has not been specified, and attempts to
allocate a message block. The
p parameter can be used, for example,
to specify how long the delay will be when an
M_DELAY message is
being sent.
putnextctl1() fails if
type is
M_DATA,
M_PROTO, or
M_PCPROTO, or if a message block cannot be allocated. If successful,
putnextctl1() calls the
put(9E) routine of the queue pointed to by
q with the newly allocated and initialized message.
A call to
putnextctl1(q,
type, p) is an atomic equivalent of
putctl1(q->q_next, type, p). The STREAMS framework provides whatever
mutual exclusion is necessary to insure that dereferencing
q through
its
q_next field and then invoking
putctl1(9F) proceeds without
interference from other threads.
The
putnextctl1() function should always be used in preference to
putctl1(9F)RETURN VALUES
On success,
1 is returned.
0 is returned if
type is a data type, or
if a message block cannot be allocated.
CONTEXT
The
putnextctl1() function can be called from user, interrupt, or
kernel context.
EXAMPLES
See the
putnextctl(9F) function page for an example of
putnextctl1().
SEE ALSO
put(9E),
allocb(9F),
datamsg(9F),
putctl1(9F),
putnextctl(9F) Writing Device Drivers STREAMS Programming Guide January 16, 2006 PUTNEXTCTL1(9F)
