t_rcv(3) — CLIX 3.1r7.6.28



  t_rcv(3)                            CLIX                            t_rcv(3)



  NAME

    t_rcv - Receives data or expedited data sent over a connection

  LIBRARY

    The Transport Layer Interface (TLI) Library (libnsl_s.a)

  SYNOPSIS

    int t_rcv(
      int fd ,
      char *buf ,
      unsigned nbytes ,
      int *flags );

  DESCRIPTION

    This function receives either normal or expedited data.  The fd parameter
    identifies the local transport endpoint through which data will arrive,
    buf points to a receive buffer where user data will be placed, and nbytes
    specifies the size of the receive buffer.  The flags parameter may be set
    on return from t_rcv() and specifies optional flags as described below.

    By default, t_rcv() operates in synchronous mode and will wait for data to
    arrive if none is currently available.  However, if O_NDELAY is set (with
    t_open() or fcntl()), t_rcv() will execute in asynchronous mode and will
    fail if no data is available.  (See TNODATA below.)

    On return from the call, if T_MORE is set in flags this indicates that
    there is more data and the current transport service data unit (TSDU) or
    expedited transport service data unit (ETSDU) must be received in multiple
    t_rcv() calls.  Each t_rcv() with the T_MORE flag set indicates that
    another t_rcv() must follow immediately to get more data for the current
    TSDU.  The end of the TSDU is identified by the return of a t_rcv() call
    with the T_MORE flag not set.  If the transport provider does not support
    the concept of a TSDU as indicated in the info structure on return from
    t_open() or t_getinfo(), the flag is not meaningful and should be ignored.

    On return, the data returned is expedited data if T_EXPEDITED is set in
    flags.  If the number of bytes of expedited data exceeds nbytes, t_rcv()
    will set T_EXPEDITED and T_MORE on return from the initial call.
    Subsequent calls to retrieve the remaining ETSDU will not have T_EXPEDITED
    set on return.  The end of the ETSDU is identified by the return of a
    t_rcv() call with the T_MORE flag not set.

    If expedited data arrives after part of a TSDU has been retrieved, receipt
    of the remainder of the TSDU will be suspended until the ETSDU has been
    processed.  Only after the full ETSDU has been retrieved (T_MORE not set)
    will the remainder of the TSDU be available to the user.




  2/94 - Intergraph Corporation                                              1



  t_rcv(3)                            CLIX                            t_rcv(3)



  RETURN VALUES

    On successful completion, t_rcv() returns the number of bytes received,
    and it returns -1 on failure and t_errno is set to indicate the error.

  ERRORS

    On failure, t_errno may be set to one of the following:

    [TBADF]
           The specified file descriptor does not refer to a transport
           endpoint.

    [TNODATA]
           O_NDELAY was set, but no data is currently available from the
           transport provider.

    [TLOOK]
           An asynchronous event has occurred on this transport endpoint and
           requires immediate attention.

    [TNOTSUPPORT]
           This function is not supported by the underlying transport
           provider.

    [TSYSERR]
           A system error has occurred during execution of this function.

  RELATED INFORMATION

    Functions: t_open(3), t_snd(3)

    AT&T UNIX System V Network Programmer's Guide





















  2                                              Intergraph Corporation - 2/94

Museum

Related Articles