1t_listen(3NSL) Networking Services Library Functions t_listen(3NSL)
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6 t_listen - listen for a connection indication
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9 #include <xti.h>
10 int t_listen(int fd, struct t_call *call);
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17 This routine is part of the XTI interfaces which evolved from the TLI
18 interfaces. XTI represents the future evolution of these interfaces.
19 However, TLI interfaces are supported for compatibility. When using a
20 TLI routine that has the same name as an XTI routine, the tiuser.h
21 header file must be used. Refer to the TLI COMPATIBILITY section for
22 a description of differences between the two interfaces.
23 This function listens for a connection indication from a calling trans‐
26 port user. The argument fd identifies the local transport endpoint
27 where connection indications arrive, and on return, call contains
28 information describing the connection indication. The parameter call
29 points to a t_call structure which contains the following members:
30 struct netbuf addr;
32 struct netbuf opt;
33 struct netbuf udata;
34 int sequence;
35 In call, addr returns the protocol address of the calling transport
39 user. This address is in a format usable in future calls to t_con‐
40 nect(3NSL). Note, however that t_connect(3NSL) may fail for other rea‐
41 sons, for example TADDRBUSY. opt returns options associated with the
42 connection indication, udata returns any user data sent by the caller
43 on the connection request, and sequence is a number that uniquely iden‐
44 tifies the returned connection indication. The value of sequence
45 enables the user to listen for multiple connection indications before
46 responding to any of them.
47 Since this function returns values for the addr, opt and udata fields
50 of call, the maxlen field of each must be set before issuing the t_lis‐
51 ten() to indicate the maximum size of the buffer for each. If the
52 maxlen field of call→addr, call→opt or call→udata is set to zero, no
53 information is returned for this parameter.
54 By default, t_listen() executes in synchronous mode and waits for a
57 connection indication to arrive before returning to the user. However,
58 if O_NONBLOCK is set via t_open(3NSL) or fcntl(2), t_listen() executes
59 asynchronously, reducing to a poll for existing connection indications.
60 If none are available, it returns -1 and sets t_errno to TNODATA.
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63 Upon successful completion, a value of 0 is returned. Otherwise, a
64 value of −1 is returned and t_errno is set to indicate an error.
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67 T_IDLE, T_INCON
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70 On failure, t_errno is set to one of the following:
71 TBADF The specified file descriptor does not refer to a trans‐
73 port endpoint.
74 TBADQLEN The argument qlen of the endpoint referenced by fd is
77 zero.
78 TBUFOVFLW The number of bytes allocated for an incoming argument
81 (maxlen) is greater than 0 but not sufficient to store
82 the value of that argument. The provider's state, as
83 seen by the user, changes to T_INCON, and the connection
84 indication information to be returned in call is dis‐
85 carded. The value of sequence returned can be used to do
86 a t_snddis(3NSL).
87 TLOOK An asynchronous event has occurred on this transport
90 endpoint and requires immediate attention.
91 TNODATA O_NONBLOCK was set, but no connection indications had
94 been queued.
95 TNOTSUPPORT This function is not supported by the underlying trans‐
98 port provider.
99 TOUTSTATE The communications endpoint referenced by fd is not in
102 one of the states in which a call to this function is
103 valid.
104 TPROTO This error indicates that a communication problem has
107 been detected between XTI and the transport provider for
108 which there is no other suitable XTI error (t_errno).
109 TQFULL The maximum number of outstanding connection indica‐
112 tions has been reached for the endpoint referenced by
113 fd. Note that a subsequent call to t_listen() may block
114 until another incoming connection indication is avail‐
115 able. This can only occur if at least one of the out‐
116 standing connection indications becomes no longer out‐
117 standing, for example through a call to t_accept(3NSL).
118 TSYSERR A system error has occurred during execution of this
121 function.
122
125 The XTI and TLI interface definitions have common names but use differ‐
126 ent header files. This, and other semantic differences between the two
127 interfaces are described in the subsections below.
128 Interface Header
130 The XTI interfaces use the header file, xti.h. TLI interfaces should
131 not use this header. They should use the header:
132 #include <tiuser.h>
134 Error Description Values
137 The t_errno values TPROT0, TBADQLEN, and TQFULL can be set by the XTI
138 interface but not by the TLI interface.
139 A t_errno value that this routine can return under different circum‐
142 stances than its XTI counterpart is TBUFOVFLW. It can be returned even
143 when the maxlen field of the corresponding buffer has been set to zero.
144 Option Buffers
146 The format of the options in an opt buffer is dictated by the transport
147 provider. Unlike the XTI interface, the TLI interface does not fix the
148 buffer format.
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_accept(3NSL), t_alloc(3NSL), t_bind(3NSL), t_connect(3NSL),
164 t_open(3NSL), t_optmgmt(3NSL), t_rcvconnect(3NSL), t_snddis(3NSL),
165 attributes(5)
166
168 Some transport providers do not differentiate between a connection
169 indication and the connection itself. If this is the case, a successful
170 return of t_listen() indicates an existing connection.
171SunOS 5.11 7 May 1998 t_listen(3NSL)