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putnextctl1(9f) [bsd man page]

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
putnextctl1(), like putctl1(9F), tests the type argument to make sure a data type has not been specified, and attempts to allocate a mes- sage 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. put- nextctl1() 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. putnextctl1() 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
putnextctl1() can be called from user or interrupt 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 SunOS 5.10 29 Mar 1993 putnextctl1(9F)

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putnextctl(9F)						   Kernel Functions for Drivers 					    putnextctl(9F)

NAME
putnextctl - send a control message to a queue SYNOPSIS
#include <sys/stream.h> int putnextctl(queue_t *q, int type); INTERFACE LEVEL
Architecture independent level 1 (DDI/DKI). PARAMETERS
q Queue to which the message is to be sent. type Message type (must be control, not data type). DESCRIPTION
putnextctl() tests the type argument to make sure a data type has not been specified, and then attempts to allocate a message block. put- nextctl() fails if type is M_DATA, M_PROTO, or M_PCPROTO, or if a message block cannot be allocated. If successful, putnextctl() calls the put(9E) routine of the queue pointed to by q with the newly allocated and initialized messages. A call to putnextctl(q,type) is an atomic equivalent of putctl(q->q_next,type). The STREAMS framework provides whatever mutual exclusion is necessary to insure that dereferencing q through its q_next field and then invoking putctl(9F) proceeds without interference from other threads. putnextctl() should always be used in preference to putctl(9F) RETURN VALUES
On success, 1 is returned. If type is a data type, or if a message block cannot be allocated, 0 is returned. CONTEXT
putnextctl() can be called from user or interrupt context. EXAMPLES
The send_ctl routine is used to pass control messages downstream. M_BREAK messages are handled with putnextctl() (line 8). put- nextctl1(9F) (line 13) is used for M_DELAY messages, so that parm can be used to specify the length of the delay. In either case, if a message block cannot be allocated a variable record- ing the number of allocation failures is incremented (lines 9, 14). If an invalid message type is detected, cmn_err(9F) panics the sys- tem (line 18). 1 void 2 send_ctl(queue_t *wrq, uchar_t type, uchar_t parm) 3 { 4 extern int num_alloc_fail; 5 6 switch (type) { 7 case M_BREAK: 8 if (!putnextctl(wrq, M_BREAK)) 9 num_alloc_fail++; 10 break; 11 12 case M_DELAY: 13 if (!putnextctl1(wrq, M_DELAY, parm)) 14 num_alloc_fail++; 15 break; 16 17 default: 18 cmn_err(CE_PANIC, "send_ctl: bad message type passed"); 19 break; 20 } 21 } SEE ALSO
put(9E), cmn_err(9F), datamsg(9F), putctl(9F), putnextctl1(9F) Writing Device Drivers STREAMS Programming Guide SunOS 5.10 29 Mar 1993 putnextctl(9F)

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