projects / thirdparty / man-pages.git / blame
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1 | .\" This man page is Copyright (C) 1999 Andi Kleen <ak@muc.de>. |
| 2 | .\" Permission is granted to distribute possibly modified copies | |
| 3 | .\" of this page provided the header is included verbatim, | |
| 4 | .\" and in case of nontrivial modification author and date | |
| 5 | .\" of the modification is added to the header. | |
| 6 | .\" $Id: udp.7,v 1.7 2000/01/22 01:55:05 freitag Exp $ | |
| 7 | .\" | |
| 402ffae3 | 8 | .TH UDP 7 2010-06-13 "Linux" "Linux Programmer's Manual" |
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9 | .SH NAME |
| 10 | udp \- User Datagram Protocol for IPv4 | |
| 11 | .SH SYNOPSIS | |
| 12 | .B #include <sys/socket.h> | |
| 13 | .br | |
| 14 | .B #include <netinet/in.h> | |
| 15 | .sp | |
| d4c8c97c | 16 | .B udp_socket = socket(AF_INET, SOCK_DGRAM, 0); |
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17 | .SH DESCRIPTION |
| 18 | This is an implementation of the User Datagram Protocol | |
| 19 | described in RFC\ 768. | |
| 20 | It implements a connectionless, unreliable datagram packet service. | |
| 21 | Packets may be reordered or duplicated before they arrive. | |
| 22 | UDP generates and checks checksums to catch transmission errors. | |
| 23 | ||
| 24 | When a UDP socket is created, | |
| 25 | its local and remote addresses are unspecified. | |
| 26 | Datagrams can be sent immediately using | |
| 27 | .BR sendto (2) | |
| 28 | or | |
| 29 | .BR sendmsg (2) | |
| 30 | with a valid destination address as an argument. | |
| 31 | When | |
| 32 | .BR connect (2) | |
| fe10db36 | 33 | is called on the socket, the default destination address is set and |
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34 | datagrams can now be sent using |
| 35 | .BR send (2) | |
| 36 | or | |
| 37 | .BR write (2) | |
| 38 | without specifying a destination address. | |
| 39 | It is still possible to send to other destinations by passing an | |
| 40 | address to | |
| 41 | .BR sendto (2) | |
| 42 | or | |
| 43 | .BR sendmsg (2). | |
| fe10db36 | 44 | In order to receive packets, the socket can be bound to a local |
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45 | address first by using |
| 46 | .BR bind (2). | |
| 47 | Otherwise the socket layer will automatically assign | |
| 48 | a free local port out of the range defined by | |