(D7str) - STREAMS message types

Intro
Introduction to STREAMS message types
M_BREAK
request that BREAK be transmitted on media
M_COPYIN
request a copyin operation
M_COPYOUT
request a copyout operation
M_CTL
send information to a particular module or type of module
M_DATA
carry ordinary data
M_DELAY
request realtime delay on output
M_ERROR
report downstream error condition
M_FLUSH
flush all message queues
M_HANGUP
report that the driver can no longer send data upstream
M_IOCACK
signal acknowledgement of M_IOCTL message
M_IOCDATA
response to an M_COPYIN or M_COPYOUT message
M_IOCNAK
negative acknowledgement of M_IOCTL message
M_IOCTL
statisfy STREAMS ioctl system calls
M_PASSFP
pass file pointer between Stream heads
M_PCCTL
send priority information to a particular module or type of module
M_PCPROTO
hold internal control information and associated data (priority)
M_PCRSE
reserved for internal use
M_PCSETOPTS
alter characteristics of the Stream head (priority)
M_PCSIG
post a high-priority signal to a process
M_PROTO
hold internal control information and associated data
M_READ
send read request downstream
M_RSE
reserved for internal use
M_SETOPTS
alter characteristics of the Stream head
M_SIG
post a signal to a process
M_START
pause or restart device output or input
M_STARTI
start device input
M_STOP
pause device output
M_STOPI
pause device input
M_TRAIL
Marks end of data after M_HANGUP message