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Annotation of coherent/a/usr/man/COHERENT/msgrcv, revision 1.1

1.1     ! root        1: 
        !             2: 
        !             3: msgrcv()               COHERENT System Call              msgrcv()
        !             4: 
        !             5: 
        !             6: 
        !             7: 
        !             8: Receive a message
        !             9: 
        !            10: #include <sys/msg.h>
        !            11: mmssggrrccvv(_m_s_q_i_d, _m_s_g_p, _m_s_g_s_z, _m_s_g_t_y_p, _m_s_g_f_l_g)
        !            12: iinntt _m_s_q_i_d, _m_s_g_s_z, _m_s_g_f_l_g; ssttrruucctt mmssggbbuuff *_m_s_g_p; lloonngg _m_s_g_t_y_p;
        !            13: 
        !            14: msgrcv reads  a message from the queue  associated with the queue
        !            15: identifier msqid  and writes  it in  the structure pointed  to by
        !            16: msgp.  This structure consists of the following members:
        !            17: 
        !            18: 
        !            19: long mtype;    /* message type */
        !            20: char mtext[];  /* message text */
        !            21: 
        !            22: 
        !            23: mtype is the received message's type, as specified by the sending
        !            24: process.  mtext is the text of the message.  msgsz gives the size
        !            25: of mtext,  in bytes.  The received message  is truncated to msgsz
        !            26: bytes if  it is larger  than msgsz and (_m_s_g_f_l_g  & MMSSGG_NNOOEERRRROORR) is
        !            27: true.  The truncated portion of  the message is lost, with no in-
        !            28: dication given to the calling process.
        !            29: 
        !            30: msgtyp specifies the type of message requested, as follows:
        !            31: 
        !            32: *   If  msgtyp equals  0L,  the  first message  on  the queue  is
        !            33:    received.
        !            34: 
        !            35: *  If msgtyp is greater than 0L, the first message of type msgtyp
        !            36:    is received.
        !            37: 
        !            38: *  If  msgtyp is less  than 0L, the  first message of  the lowest
        !            39:    type  that is  less than  or  equal to  the absolute  value of
        !            40:    msgtyp is received.
        !            41: 
        !            42: msgflg specifies  the action  taken if  a message of  the desired
        !            43: type is not on the queue, as follows:
        !            44: 
        !            45: *   If (_m_s_g_f_l_g  & IIPPCC_NNOOWWAAIITT)  is true,  the calling  process im-
        !            46:    mediately returns -1 and sets errno to ENOMSG.
        !            47: 
        !            48: *   If  (_m_s_g_f_l_g  &  IIPPCC_NNOOWWAAIITT)  is  false, the  calling  process
        !            49:    suspends execution until one of the following occurs:
        !            50: 
        !            51: 11. A message of the desired type is placed on the queue.
        !            52: 
        !            53: 22. msqid  is removed from  the system.  When  this occurs, msgrcv
        !            54:    sets errno to EDOM
        !            55: 
        !            56: 33. The  calling process receives  a signal that is  to be caught.
        !            57:    In  this  case, a  message  is not  received  and the  calling
        !            58:    process resumes execution in the manner prescribed in signal.
        !            59: 
        !            60: msgrcv fails  and no message is received if  any of the following
        !            61: is true:
        !            62: 
        !            63: 
        !            64: COHERENT Lexicon                                           Page 1
        !            65: 
        !            66: 
        !            67: 
        !            68: 
        !            69: msgrcv()               COHERENT System Call              msgrcv()
        !            70: 
        !            71: 
        !            72: 
        !            73: 
        !            74: *  msqid  is not a valid message  queue identifier.  msgrcv errno
        !            75:    to EINVAL.
        !            76: 
        !            77: *   Operation  permission   is  denied  to  the  calling  process
        !            78:    (EEAACCCCEESS).
        !            79: 
        !            80: *  msgsz is less than zero (EEIINNVVAALL).
        !            81: 
        !            82: *   mtext is  greater than  msgsz and  (_m_s_g_f_l_g &  MMSSGG_NNOOEERRRROORR) is
        !            83:    false (EE22BBIIGG).
        !            84: 
        !            85: *  The queue  does not contain a message of  the desired type and
        !            86:    (_m_s_g_t_y_p & IIPPCC_NNOOWWAAIITT) is true (EENNOOMMSSGG).
        !            87: 
        !            88: *  msgp points to an illegal address (EEFFAAUULLTT).
        !            89: 
        !            90: Upon successful completion,  the following actions are taken with
        !            91: respect to the data structure associated with msqid:
        !            92: 
        !            93: *  msg_qnum is decremented by one.
        !            94: 
        !            95: *   msg_lrpid  is set  equal  to the  process  identifier of  the
        !            96:    calling process.
        !            97: 
        !            98: *  msg_rtime is set equal to the current time.
        !            99: 
        !           100: ***** Return Values *****
        !           101: 
        !           102: If msgrcv returns  due to the receipt of a  signal, it returns -1
        !           103: and sets  errno to EINTR.   If it returns  due to the  removal of
        !           104: msqid  from the  system, it  returns -1 and  sets errno  to EDOM.
        !           105: Upon successful  completion, msgrcv returns a  value equal to the
        !           106: number of bytes written into mtext.  Otherwise, it returns -1 and
        !           107: sets errno to an appropriate value.
        !           108: 
        !           109: ***** Files *****
        !           110: 
        !           111: /usr/include/sys/ipc.h
        !           112: /usr/include/sys/msg.h
        !           113: /dev/msg
        !           114: 
        !           115: ***** See Also *****
        !           116: 
        !           117: COHERENT system calls, msg, msgctl(), msgget(), msgsnd()
        !           118: 
        !           119: ***** Notes *****
        !           120: 
        !           121: To improve portability, the COHERENT system implements the mmssgg as
        !           122: a device driver rather than as an actual system call.
        !           123: 
        !           124: 
        !           125: 
        !           126: 
        !           127: 
        !           128: 
        !           129: 
        !           130: COHERENT Lexicon                                           Page 2
        !           131: 
        !           132: 

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