t_rcv(3N) t_rcv(3N)
NAME
trcv - receive data or expedited data sent over a connection
SYNOPSIS
#include <sys/tiuser.h>
int trcv(int fd, char *buf, unsigned nbytes, int *flags);
DESCRIPTION
This function receives either normal or expedited data. fd 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. flags may be set on return
from trcv and specifies optional flags as described below.
By default, trcv operates in synchronous mode and will wait for data
to arrive if none is currently available. However, if ONDELAY or
ONONBLOCK is set (via topen or fcntl), trcv will execute in asyn-
chronous mode and will fail if no data is available. (See TNODATA
below.)
On return from the call, if TMORE 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 trcv calls. Each trcv with the TMORE flag set
indicates that another trcv must follow to get more data for the
current TSDU. The end of the TSDU is identified by the return of a
trcv call with the TMORE flag not set. If the transport provider
does not support the concept of a TSDU as indicated in the info argu-
ment on return from topen or tgetinfo, the TMORE flag is not mean-
ingful and should be ignored.
On return, the data returned is expedited data if TEXPEDITED is set
in flags. If the number of bytes of expedited data exceeds nbytes,
trcv will set TEXPEDITED and TMORE on return from the initial call.
Subsequent calls to retrieve the remaining ETSDU will have TEXPEDITED
set on return. The end of the ETSDU is identified by the return of a
trcv call with the TMORE 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
(TMORE not set) will the remainder of the TSDU be available to the
user.
ERRORS
On failure, terrno may be set to one of the following:
TBADF The specified file descriptor does not refer to a
transport endpoint.
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t_rcv(3N) t_rcv(3N)
TNODATA ONDELAY or ONONBLOCK 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.
DIAGNOSTICS
On successful completion, trcv returns the number of bytes received,
and it returns -1 on failure and terrno is set to indicate the error.
SEE ALSO
topen(3N), tsnd(3N).
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