projects / unix-history / blame
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1 | .\" Copyright (c) 1983 The Regents of the University of California. |
| 2 | .\" All rights reserved. | |
| cf65baf0 | 3 | .\" |
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4 | .\" Redistribution and use in source and binary forms are permitted |
| 5 | .\" provided that the above copyright notice and this paragraph are | |
| 6 | .\" duplicated in all such forms and that any documentation, | |
| 7 | .\" advertising materials, and other materials related to such | |
| 8 | .\" distribution and use acknowledge that the software was developed | |
| 9 | .\" by the University of California, Berkeley. The name of the | |
| 10 | .\" University may not be used to endorse or promote products derived | |
| 11 | .\" from this software without specific prior written permission. | |
| 12 | .\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR | |
| 13 | .\" IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED | |
| 14 | .\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. | |
| 15 | .\" | |
| 16 | .\" @(#)listen.2 6.3 (Berkeley) %G% | |
| cf65baf0 | 17 | .\" |
| ca13daa8 | 18 | .TH LISTEN 2 "" |
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19 | .UC 5 |
| 20 | .SH NAME | |
| 21 | listen \- listen for connections on a socket | |
| 22 | .SH SYNOPSIS | |
| 23 | .nf | |
| 24 | .ft B | |
| 25 | listen(s, backlog) | |
| 26 | int s, backlog; | |
| 27 | .fi | |
| 28 | .SH DESCRIPTION | |
| 29 | To accept connections, a socket | |
| 30 | is first created with | |
| 31 | .IR socket (2), | |
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32 | a willingness to accept incoming connections and |
| 33 | a queue limit for incoming connections are specified with | |
| 34 | .IR listen (2), | |
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35 | and then the connections are |
| 36 | accepted with | |
| 37 | .IR accept (2). | |
| 38 | The | |
| 39 | .I listen | |
| 40 | call applies only to sockets of type | |
| 41 | SOCK_STREAM | |
| 42 | or | |
| 3fa31615 | 43 | SOCK_SEQPACKET. |
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44 | .PP |
| 45 | The | |
| 46 | .I backlog | |
| 47 | parameter defines the maximum length the queue of | |
| 48 | pending connections may grow to. | |
| 49 | If a connection | |
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50 | request arrives with the queue full the client may |
| 51 | receive an error with an indication of ECONNREFUSED, | |
| 52 | or, if the underlying protocol supports retransmission, | |
| 53 | the request may be ignored so that retries may succeed. | |
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54 | .SH "RETURN VALUE |
| 55 | A 0 return value indicates success; \-1 indicates an error. | |
| 56 | .SH "ERRORS | |
| 57 | The call fails if: | |
| 58 | .TP 20 | |
| 59 | [EBADF] | |
| 60 | The argument \fIs\fP is not a valid descriptor. | |
| 61 | .TP 20 | |
| 62 | [ENOTSOCK] | |
| 63 | The argument \fIs\fP is not a socket. | |
| 64 | .TP 20 | |
| 65 | [EOPNOTSUPP] | |
| 66 | The socket is not of a type that supports the operation \fIlisten\fP. | |
| 67 | .SH "SEE ALSO" | |
| 68 | accept(2), connect(2), socket(2) | |
| 69 | .SH BUGS | |
| 70 | The | |
| 71 | .I backlog | |
| 72 | is currently limited (silently) to 5. |