Networking Services Library Functions t_rcvv(3NSL)
NAME
t_rcvv - receive data or expedited data sent over a connec-
tion and put the data into one or more non-contiguous
buffersSYNOPSIS
#include
int t_rcvv(int fd, struct t_iovec *iov, unsigned int iovcount, int *flags);
DESCRIPTION
This function receives either normal or expedited data. The argument fd identifies the local transport endpoint through which data will arrive, iov points to an array of bufferaddress/buffer size pairs (iov_base, iov_len). The t_rcvv()
function receives data into the buffers specified byiov0.iov_base, iov1.iov_base, through iov [iovcount-
1].iov_base, always filling one buffer before proceeding to
the next. Note that the limit on the total number of bytes available in all buffers passed:iov(0).iov_len + . . + iov(iovcount-1).iov_len)
may be constrained by implementation limits. If no otherconstraint applies, it will be limited by INT_MAX. In prac-
tice, the availability of memory to an application is likely to impose a lower limit on the amount of data that can be sent or received using scatter/gather functions. The argument iovcount contains the number of buffers whichis limited to T_IOV_MAX, which is an implementation-defined
value of at least 16. If the limit is exceeded, the func-
tion will fail with TBADDATA.The argument flags may be set on return from t_rcvv() and
specifies optional flags as described below.By default, t_rcvv() operates in synchronous mode and will
wait for data to arrive if none is currently available. How-
ever, if O_NONBLOCK is set by means of t_open(3NSL) or
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Networking Services Library Functions t_rcvv(3NSL)
fcntl(2), t_rcvv() 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 dataunit (ETSDU) must be received in multiple t_rcvv() or
t_rcv(3NSL) calls. In the asynchronous mode, or under
unusual conditions (for example, the arrival of a signal orT_EXDATA event), the T_MORE flag may be set on return from
the t_rcvv() call even when the number of bytes received is
less than the total size of all the receive buffers. Eacht_rcvv() with the T_MORE flag set indicates that another
t_rcvv() must follow to get more data for the current TSDU.
The end of the TSDU is identified by the return of at_rcvv() call with the T_MORE flag not set. If the tran-
sport provider does not support the concept of a TSDU asindicated in the info argument on return from t_open(3NSL)
or t_getinfo(3NSL), the T_MORE flag is not meaningful and
should be ignored. If the amount of buffer space passed iniov is greater than zero on the call to t_rcvv(), then
t_rcvv() will return 0 only if the end of a TSDU is being
returned to the user.On return, the data is expedited if T_EXPEDITED is set in
flags. If T_MORE is also set, it indicates that the number
of expedited bytes exceeded nbytes, a signal has interrupted the call, or that an entire ETSDU was not available (only for transport protocols that support fragmentation ofETSDUs). The rest of the ETSDU will be returned by subse-
quent calls to t_rcvv() which will return with T_EXPEDITED
set in flags. The end of the ETSDU is identified by thereturn of a t_rcvv() call with T_EXPEDITED set and T_MORE
cleared. If the entire ETSDU is not available it is possi-
ble for normal data fragments to be returned between the initial and final fragments of an ETSDU.If a signal arrives, t_rcvv() returns, giving the user any
data currently available. If no data is available,t_rcvv() returns -1, sets t_errno to TSYSERR and errno to
EINTR. If some data is available, t_rcvv() returns the
number of bytes received and T_MORE is set in flags.
In synchronous mode, the only way for the user to be noti-
fied of the arrival of normal or expedited data is to issuethis function or check for the T_DATA or T_EXDATA events
using the t_look(3NSL) function. Additionally, the process
can arrange to be notified via the EM interface.SunOS 5.11 Last change: 7 May 1998 2
Networking Services Library Functions t_rcvv(3NSL)
RETURN VALUES
On successful completion, t_rcvv() returns the number of
bytes received. Otherwise, it returns -1 on failure and
t_errno is set to indicate the error.
VALID STATEST_DATAXFER, T_OUTREL.
ERRORS
On failure, t_errno is set to one of the following:
TBADDATA iovcount is greater than T_IOV_MAX.
TBADF The specified file descriptor does not refer to a transport endpoint. TLOOK An asynchronous event has occurred on this transport endpoint and requires immediate attention.TNODATA O_NONBLOCK was set, but no data is currently
available from the transport provider.TNOTSUPPORT This function is not supported by the under-
lying transport provider. TOUTSTATE The communications endpoint referenced by fd is not in one of the states in which a call to this function is valid. TPROTO This error indicates that a communication problem has been detected between XTI and the transport provider for which there is noother suitable XTI error (t_errno).
TSYSERR A system error has occurred during execution of this function. TLI COMPATIBILITYIn the TLI interface definition, no counterpart of this rou-
tine was defined.ATTRIBUTES
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Networking Services Library Functions t_rcvv(3NSL)
See attributes(5) for descriptions of the following attri-
butes:____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| MT Level | Safe ||_____________________________|_____________________________|
SEE ALSO
fcntl(2), t_getinfo(3NSL), t_look(3NSL), t_open(3NSL),
t_rcv(3NSL), t_snd(3NSL), t_sndv(3NSL), attributes(5)
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