send(3xnet) - osol9

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

6       send - send a message on a socket
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SYNOPSIS

9       cc [ flag ... ] file ... -lxnet [ library ... ]
10       #include <sys/socket.h>
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12       ssize_t send(int socket, const void *buffer, size_t length, int flags);
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PARAMETERS

16       socket    Specifies the socket file descriptor.
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19       buffer    Points to the buffer containing the message to send.
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22       length    Specifies the length of the message in bytes.
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25       flags     Specifies  the  type  of message transmission. Values of this
26                 argument are formed by logically OR'ing zero or more  of  the
27                 following flags:
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29                 MSG_EOR    Terminates a record (if supported by the protocol)
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32                 MSG_OOB    Sends  out-of-band  data  on  sockets that support
33                            out-of-band communications. The  significance  and
34                            semantics  of  out-of-band  data are protocol-spe‐
35                            cific.
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DESCRIPTION

40       The send() function initiates transmission of a message from the speci‐
41       fied socket to its peer.  The send() function sends a message only when
42       the socket is connected (including when the peer  of  a  connectionless
43       socket has been set via connect(3XNET)).
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46       The  length  of the message to be sent is specified by the length argu‐
47       ment. If the message is too long to pass through the underlying  proto‐
48       col, send() fails and no data is transmitted.
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51       Successful  completion  of a call to send() does not guarantee delivery
52       of the message.  A return value of −1 indicates  only  locally-detected
53       errors.
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56       If  space is not available at the sending socket to hold the message to
57       be transmitted and the socket file descriptor does not have  O_NONBLOCK
58       set, send() blocks until space is available.  If space is not available
59       at the sending socket to hold the message to  be  transmitted  and  the
60       socket  file descriptor does have O_NONBLOCK set, send() will fail. The
61       select(3C) and poll(2) functions can be used to determine  when  it  is
62       possible to send more data.
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65       The  socket  in  use may require the process to have appropriate privi‐
66       leges to use the send() function.
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USAGE

69       The send() function is identical to sendto(3XNET) with a  null  pointer
70       dest_len argument, and to write() if no flags are used.
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RETURN VALUES

73       Upon  successful  completion,  send() returns the number of bytes sent.
74       Otherwise, −1 is returned and errno is set to indicate the error.
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ERRORS

77       The send() function will fail if:
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79       EAGAIN          The socket's file descriptor is marked  O_NONBLOCK  and
80       EWOULDBLOCK     the requested operation would block.
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83       EBADF           The socket argument is not a valid file descriptor.
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86       ECONNRESET      A connection was forcibly closed by a peer.
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89       EDESTADDRREQ    The  socket  is not connection-mode and no peer address
90                       is set.
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93       EFAULT          The  buffer parameter can not be accessed.
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96       EINTR           A signal interrupted send() before any data was  trans‐
97                       mitted.
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100       EMSGSIZE        The  message  is  too large be sent all at once, as the
101                       socket requires.
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104       ENOTCONN        The socket is not connected or otherwise  has  not  had
105                       the peer prespecified.
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108       ENOTSOCK        The socket argument does not refer to a socket.
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111       EOPNOTSUPP      The  socket  argument  is associated with a socket that
112                       does not support one or  more  of  the  values  set  in
113                       flags.
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116       EPIPE           The  socket  is shut down for writing, or the socket is
117                       connection-mode and is no longer connected. In the lat‐
118                       ter case, and if the socket is of type SOCK_STREAM, the
119                       SIGPIPE signal is generated to the calling thread.
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123       The send() function may fail if:
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125       EACCES         The calling process does not have the appropriate privi‐
126                      leges.
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129       EIO            An  I/O  error occurred while reading from or writing to
130                      the file system.
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133       ENETDOWN       The local interface used to  reach  the  destination  is
134                      down.
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137       ENETUNREACH    No route to the network is present.
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140       ENOBUFS        Insufficient  resources  were available in the system to
141                      perform the operation.
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144       ENOSR          There were insufficient STREAMS resources available  for
145                      the operation to complete.
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ATTRIBUTES

149       See attributes(5) for descriptions of the following attributes:
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154       ┌─────────────────────────────┬─────────────────────────────┐
155       │      ATTRIBUTE TYPE         │      ATTRIBUTE VALUE        │
156       ├─────────────────────────────┼─────────────────────────────┤
157       │Interface Stability          │Standard                     │
158       ├─────────────────────────────┼─────────────────────────────┤
159       │MT-Level                     │MT-Safe                      │
160       └─────────────────────────────┴─────────────────────────────┘
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