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diff --git a/docs/reference/src/compat/nn_send.3compat.adoc b/docs/reference/src/compat/nn_send.3compat.adoc
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+= nn_send(3compat)
+//
+// Copyright 2018 Staysail Systems, Inc. <info@staysail.tech>
+// Copyright 2018 Capitar IT Group BV <info@capitar.com>
+//
+// This document is supplied under the terms of the MIT License, a
+// copy of which should be located in the distribution where this
+// file was obtained (LICENSE.txt).  A copy of the license may also be
+// found online at https://opensource.org/licenses/MIT.
+//
+
+== NAME
+
+nn_send - send data (compatible API)
+
+== SYNOPSIS
+
+[source, c]
+----
+#include <nanomsg/nn.h>
+
+int nn_send(int sock, const void *data, size_t size, int flags)
+----
+
+== DESCRIPTION
+
+The `nn_send()` function creates a message containing _data_ (of size _size_),
+and sends using the socket _sock_.
+
+NOTE: This function is provided for API
+xref:nng_compat.3compat.adoc[compatibility] with legacy _libnanomsg_.
+Consider using the relevant xref:libnng.3.adoc[modern API] instead.
+
+If _size_ has the special value `NN_MSG`, then a zero-copy operation
+is performed.
+In this case, _data_ points not to the message content itself, but instead
+is a pointer to the pointer, an extra level of pointer indirection.
+The message must have been previously allocated by
+xref:nn_allocmsg.3compat.adoc[`nn_allocmsg()`] or
+xref:nn_recvmsg.3compat.adoc[`nn_recvmsg()`]`, using the same `NN_MSG` size.
+In this case, the ownership of the message shall remain with
+the caller, unless the function returns 0, indicating that the
+function has taken responsibility for delivering or disposing of the
+message.
+
+The _flags_ field may contain the special flag `NN_DONTWAIT`.
+In this case, if the socket is unable to accept more data for sending,
+the operation shall not block, but instead will fail with the error `EAGAIN`.
+
+NOTE: The send operation is performed asynchronously, and may not have
+completed before this function returns control to the caller.
+
+== RETURN VALUES
+
+This function returns the number of bytes sent on success, and -1 on error.
+
+== ERRORS
+
+[horizontal]
+`EAGAIN`:: The operation would block.
+`EBADF`:: The socket _sock_ is not open.
+`EFSM`:: The socket cannot send in this state.
+`ENOTSUP`:: This protocol cannot send.
+`ETIMEDOUT`:: Operation timed out.
+
+== SEE ALSO
+
+[.text-left]
+xref:nn_errno.3compat.adoc[nn_errno(3compat)],
+xref:nn_recv.3compat.adoc[nn_recv(3compat)],
+xref:nn_sendmsg.3compat.adoc[nn_sendmsg(3compat)],
+xref:nn_socket.3compat.adoc[nn_socket(3compat)],
+xref:nng_compat.3compat.adoc[nn_compat(3compat)],
+xref:nng.7.adoc[nng(7)]