(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 ordinary information to a particular module or type of module
M_CTL, M_PCCTL: 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_HANGUP, M_TRAIL: report that the driver can no longer send data upstream
M_IOCACK: positive acknowledgement of M_IOCTL message
M_IOCACK, M_IOCNAK: 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 (non-priority)
M_PROTO, M_PCPROTO: 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 (ordinary)
M_SETOPTS, M_PCSETOPTS: alter characteristics of the Stream head
M_SIG: post ordinary priority signal to a process
M_SIG, M_PCSIG: post a signal to a process
M_START: start device output
M_STARTI: start device input
M_START, M_STOP, M_STARTI, M_STOPI: pause or restart device output or input
M_STOP: pause device output
M_STOPI: pause device input
M_TRAIL: Marks end of data after M_HANGUP message