socket(3xnet)

1socket(3XNET)    X/Open Networking Services Library Functions    socket(3XNET)
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NAME

6       socket - create an endpoint for communication
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SYNOPSIS

9       cc [ flag ... ] file ... -lxnet [ library ... ]
10       #include <sys/socket.h>
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12       int socket(int domain, int type, int protocol);
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DESCRIPTION

16       The  socket()  function  creates  an unbound socket in a communications
17       domain, and returns a file descriptor that can be used in  later  func‐
18       tion calls that operate on sockets.
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21       The <sys/socket.h> header defines at least the following values for the
22       domain argument:
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24       AF_UNIX     File system pathnames.
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27       AF_INET     Internet Protocol version 4 (IPv4) address.
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30       AF_INET6    Internet Protocol version 6 (IPv6) address.
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34       The type argument specifies  the  socket  type,  which  determines  the
35       semantics of communication over the socket.  The socket types supported
36       by the system  are  implementation-dependent.   Possible  socket  types
37       include:
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39       SOCK_STREAM       Provides  sequenced, reliable, bidirectional, connec‐
40                         tion-mode byte streams, and may provide  a  transmis‐
41                         sion mechanism for out-of-band data.
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44       SOCK_DGRAM        Provides  datagrams,  which  are connectionless-mode,
45                         unreliable messages of fixed maximum length.
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48       SOCK_SEQPACKET    Provides sequenced, reliable, bidirectional,  connec‐
49                         tion-mode  transmission  path  for records.  A record
50                         can be sent using one or more output  operations  and
51                         received  using  one  or more input operations, but a
52                         single operation never transfers part  of  more  than
53                         one  record.   Record  boundaries  are visible to the
54                         receiver via the MSG_EOR flag.
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58       If the protocol argument is non-zero, it must specify a  protocol  that
59       is  supported  by  the  address family.  The protocols supported by the
60       system are implementation-dependent.
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63       The process may need to have appropriate privileges to use the socket()
64       function or to create some sockets.
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PARAMETERS

67       The function takes the following arguments:
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69       domain      Specifies the communications domain in which a socket is to
70                   be created.
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73       type        Specifies the type of socket to be created.
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76       protocol    Specifies a particular protocol to be used with the socket.
77                   Specifying  a  protocol  of  0  causes  socket()  to use an
78                   unspecified default protocol appropriate for the  requested
79                   socket type.
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83       The domain argument specifies the address family used in the communica‐
84       tions domain.  The address families supported by the system are  imple‐
85       mentation-dependent.
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USAGE

88       The documentation for specific address families specify which protocols
89       each address family supports.  The documentation for specific protocols
90       specify which socket types each protocol supports.
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93       The application can determine if an address family is supported by try‐
94       ing to create a socket with domain set to the protocol in question.
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RETURN VALUES

97       Upon successful completion, socket() returns a nonnegative integer, the
98       socket  file descriptor.  Otherwise a value of -1 is returned and errno
99       is set to indicate the error.
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ERRORS

102       The socket() function will fail if:
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104       EAFNOSUPPORT       The implementation does not  support  the  specified
105                          address family.
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108       EMFILE             No  more  file  descriptors  are  available for this
109                          process.
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112       ENFILE             No more file descriptors are available for the  sys‐
113                          tem.
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116       EPROTONOSUPPORT    The protocol is not supported by the address family,
117                          or the protocol is not supported by the  implementa‐
118                          tion.
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121       EPROTOTYPE         The socket type is not supported by the protocol.
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125       The socket() function may fail if:
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127       EACCES     The process does not have appropriate privileges.
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130       ENOBUFS    Insufficient  resources were available in the system to per‐
131                  form the operation.
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134       ENOMEM     Insufficient memory was available to fulfill the request.
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137       ENOSR      There were insufficient STREAMS resources available for  the
138                  operation to complete.
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ATTRIBUTES

142       See attributes(5) for descriptions of the following attributes:
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147       ┌─────────────────────────────┬─────────────────────────────┐
148       │      ATTRIBUTE TYPE         │      ATTRIBUTE VALUE        │
149       ├─────────────────────────────┼─────────────────────────────┤
150       │Interface Stability          │Standard                     │
151       ├─────────────────────────────┼─────────────────────────────┤
152       │MT-Level                     │MT-Safe                      │
153       └─────────────────────────────┴─────────────────────────────┘
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