fixes #303 Flesh out compatible API docs

1 files changed, 74 insertions, 0 deletions

diff --git a/docs/man/nn_recv.3compat.adoc b/docs/man/nn_recv.3compat.adoc
new file mode 100644
index 00000000..8b873f8f
--- /dev/null
+++ b/docs/man/nn_recv.3compat.adoc
@@ -0,0 +1,74 @@
+= nn_recv(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 - receive data (compatible API)
+
+== SYNOPSIS
+
+[source, c]
+----
+#include <nanomsg/nn.h>
+
+int nn_recv(int sock, void *data, size_t size, int flags)
+----
+
+== DESCRIPTION
+
+The `nn_recv()` function receives a message from the socket _sock_.
+The message body must fit within _size_ bytes, and will be stored
+at the location specified by _data_, unless _size_ is the
+special value `NN_MSG`, indicating a zero-copy operation.
+
+NOTE: This function is provided for API
+<<nng_compat.3compat#,compatibility>> with legacy _libnanomsg_.
+Consider using the relevant <<libnng.3#,modern API>> instead.
+
+If _size_ has the special value `NN_MSG`, then a zero-copy operation
+is performed.
+In this case, instead of copying the message data into the address
+specified by _data_, a new message large enough to hold the message data
+will be allocated (as if by the
+function `<<nn_allocmsg.3compat#,nn_allocmsg()>>`), and the message
+payload will be stored accordingly.
+In this case, the value stored at _data_ will not be message data,
+but a pointer to the message itself.
+In this case, on success, the caller shall take responsibility for
+the final disposition of the message (such as by sending it to
+another peer using `<<nn_send.3compat#,nn_send()>>`) or
+`<<nn_freemsg.3compat#,nn_freemsg()>>`.
+
+The _flags_ field may contain the special flag `NN_DONTWAIT`.
+In this case, if the no message is available for immediate receipt,
+the operation shall not block, but instead will fail with the error `EAGAIN`.
+
+== 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 receive in this state.
+`ENOTSUP`:: This protocol cannot receive.
+`ETIMEDOUT`:: Operation timed out.
+
+== SEE ALSO
+
+<<nn_errno.3compat#,nn_errno(3compat)>>,
+<<nn_recvmsg.3compat#,nn_recvmsg(3compat)>>,
+<<nn_send.3compat#,nn_send(3compat)>>,
+<<nn_socket.3compat#,nn_socket(3compat)>>,
+<<nng_compat.3compat#,nn_compat(3compat)>>,
+<<nng.7#,nng(7)>>