1t_rcvv(3NSL) Networking Services Library Functions t_rcvv(3NSL)
2
6 t_rcvv - receive data or expedited data sent over a connection and put
7 the data into one or more non-contiguous buffers
8
10 #include <xti.h>
11 int t_rcvv(int fd, struct t_iovec *iov, unsigned int iovcount, int *flags);
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19 This function receives either normal or expedited data. The argument
20 fd identifies the local transport endpoint through which data will
21 arrive, iov points to an array of buffer address/buffer size pairs
22 (iov_base, iov_len). The t_rcvv() function receives data into the buf‐
23 fers specified by iov0.iov_base, iov1.iov_base, through iov [iov‐
24 count-1].iov_base, always filling one buffer before proceeding to the
25 next.
26 Note that the limit on the total number of bytes available in all buf‐
29 fers passed:
30 iov(0).iov_len + . . + iov(iovcount-1).iov_len)
32 may be constrained by implementation limits. If no other constraint
36 applies, it will be limited by INT_MAX. In practice, the availability
37 of memory to an application is likely to impose a lower limit on the
38 amount of data that can be sent or received using scatter/gather func‐
39 tions.
40 The argument iovcount contains the number of buffers which is limited
43 to T_IOV_MAX, which is an implementation-defined value of at least
44 16. If the limit is exceeded, the function will fail with TBADDATA.
45 The argument flags may be set on return from t_rcvv() and specifies
48 optional flags as described below.
49 By default, t_rcvv() operates in synchronous mode and will wait for
52 data to arrive if none is currently available. However, if O_NONBLOCK
53 is set by means of t_open(3NSL) or fcntl(2), t_rcvv() will execute in
54 asynchronous mode and will fail if no data is available. See TNODATA
55 below.
56 On return from the call, if T_MORE is set in flags, this indicates
59 that there is more data, and the current transport service data unit
60 (TSDU) or expedited transport service data unit (ETSDU) must be
61 received in multiple t_rcvv() or t_rcv(3NSL) calls. In the asynchro‐
62 nous mode, or under unusual conditions (for example, the arrival of a
63 signal or T_EXDATA event), the T_MORE flag may be set on return from
64 the t_rcvv() call even when the number of bytes received is less than
65 the total size of all the receive buffers. Each t_rcvv() with the
66 T_MORE flag set indicates that another t_rcvv() must follow to get
67 more data for the current TSDU. The end of the TSDU is identified by
68 the return of a t_rcvv() call with the T_MORE flag not set. If the
69 transport provider does not support the concept of a TSDU as indicated
70 in the info argument on return from t_open(3NSL) or t_getinfo(3NSL),
71 the T_MORE flag is not meaningful and should be ignored. If the
72 amount of buffer space passed in iov is greater than zero on the call
73 to t_rcvv(), then t_rcvv() will return 0 only if the end of a TSDU is
74 being returned to the user.
75 On return, the data is expedited if T_EXPEDITED is set in flags. If
78 T_MORE is also set, it indicates that the number of expedited bytes
79 exceeded nbytes, a signal has interrupted the call, or that an entire
80 ETSDU was not available (only for transport protocols that support
81 fragmentation of ETSDUs). The rest of the ETSDU will be returned by
82 subsequent calls to t_rcvv() which will return with T_EXPEDITED set in
83 flags. The end of the ETSDU is identified by the return of a t_rcvv()
84 call with T_EXPEDITED set and T_MORE cleared. If the entire ETSDU is
85 not available it is possible for normal data fragments to be returned
86 between the initial and final fragments of an ETSDU.
87 If a signal arrives, t_rcvv() returns, giving the user any data cur‐
90 rently available. If no data is available, t_rcvv() returns -1, sets
91 t_errno to TSYSERR and errno to EINTR. If some data is available,
92 t_rcvv() returns the number of bytes received and T_MORE is set in
93 flags.
94 In synchronous mode, the only way for the user to be notified of the
97 arrival of normal or expedited data is to issue this function or check
98 for the T_DATA or T_EXDATA events using the t_look(3NSL) function.
99 Additionally, the process can arrange to be notified via the EM inter‐
100 face.
101
103 On successful completion, t_rcvv() returns the number of bytes
104 received. Otherwise, it returns -1 on failure and t_errno is set to
105 indicate the error.
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108 T_DATAXFER, T_OUTREL.
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111 On failure, t_errno is set to one of the following:
112 TBADDATA iovcount is greater than T_IOV_MAX.
114 TBADF The specified file descriptor does not refer to a trans‐
117 port endpoint.
118 TLOOK An asynchronous event has occurred on this transport
121 endpoint and requires immediate attention.
122 TNODATA O_NONBLOCK was set, but no data is currently available
125 from the transport provider.
126 TNOTSUPPORT This function is not supported by the underlying trans‐
129 port provider.
130 TOUTSTATE The communications endpoint referenced by fd is not in
133 one of the states in which a call to this function is
134 valid.
135 TPROTO This error indicates that a communication problem has
138 been detected between XTI and the transport provider for
139 which there is no other suitable XTI error (t_errno).
140 TSYSERR A system error has occurred during execution of this
143 function.
144
147 In the TLI interface definition, no counterpart of this routine was
148 defined.
149
151 See attributes(5) for descriptions of the following attributes:
152 ┌─────────────────────────────┬─────────────────────────────┐
157 │ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
158 ├─────────────────────────────┼─────────────────────────────┤
159 │MT Level │Safe │
160 └─────────────────────────────┴─────────────────────────────┘
161
163 fcntl(2), t_getinfo(3NSL), t_look(3NSL), t_open(3NSL), t_rcv(3NSL),
164 t_snd(3NSL), t_sndv(3NSL), attributes(5)
165SunOS 5.11 7 May 1998 t_rcvv(3NSL)