nn_send(3)

1NN_SEND(3)                       nanomsg 1.1.5                      NN_SEND(3)
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NAME

6       nn_send - send a message
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SYNOPSIS

9       #include <nanomsg/nn.h>
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11       int nn_send (int s, const void *buf, size_t len, int flags);
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DESCRIPTION

14       The function will send a message containing the data from buffer
15       pointed to by buf parameter to the socket s. The message will be len
16       bytes long.
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18       Alternatively, to send a buffer allocated by nn_allocmsg(3) function
19       set the buf parameter to point to the pointer to the buffer and len
20       parameter to NN_MSG constant. In this case a successful call to nn_send
21       will deallocate the buffer. Trying to deallocate it afterwards will
22       result in undefined behaviour.
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24       Which of the peers the message will be sent to is determined by the
25       particular socket type.
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27       The flags argument is a combination of the flags defined below:
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29       NN_DONTWAIT
30           Specifies that the operation should be performed in non-blocking
31           mode. If the message cannot be sent straight away, the function
32           will fail with errno set to EAGAIN.
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RETURN VALUE

35       If the function succeeds, the number of bytes in the message is
36       returned. Otherwise, -1 is returned and errno is set to to one of the
37       values defined below.
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ERRORS

40       EFAULT
41           buf is NULL or len is NN_MSG and the message pointer (pointed to by
42           buf) is NULL.
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44       EBADF
45           The provided socket is invalid.
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47       ENOTSUP
48           The operation is not supported by this socket type.
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50       EFSM
51           The operation cannot be performed on this socket at the moment
52           because the socket is not in the appropriate state. This error may
53           occur with socket types that switch between several states.
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55       EAGAIN
56           Non-blocking mode was requested and the message cannot be sent at
57           the moment.
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59       EINTR
60           The operation was interrupted by delivery of a signal before the
61           message was sent.
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63       ETIMEDOUT
64           Individual socket types may define their own specific timeouts. If
65           such timeout is hit, this error will be returned.
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67       ETERM
68           The library is terminating.
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EXAMPLE

71       Using data directly:
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73           nbytes = nn_send (s, "ABC", 3, 0);
74           assert (nbytes == 3);
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76       Using a pre-allocated message buffer:
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78           void *msg = nn_allocmsg(3, 0);
79           strncpy(msg, "ABC", 3);
80           nbytes = nn_send (s, &msg, NN_MSG, 0);
81           assert (nbytes == 3);
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AUTHORS

87       Martin Sustrik <sustrik@250bpm.com>
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91                                  2021-01-26                        NN_SEND(3)