Add nng_sendmsg and nng_recvmsg manual pages.

3 files changed, 156 insertions, 1 deletions

diff --git a/docs/man/libnng.adoc b/docs/man/libnng.adoc
index 72516705..0c5ee75f 100644
--- a/docs/man/libnng.adoc
+++ b/docs/man/libnng.adoc
@@ -90,7 +90,7 @@ Most applications will only interact with the body.
 |<<nng_msg_len#,nng_msg_len(3)>>|return the message body length
 |<<nng_msg_realloc#,nng_msg_realloc(3)>>|reallocate a message
 |<<nng_msg_trim#,nng_msg_trim(3)>>|remove data from start of message body
-|<<nng_recv_msg#,nng_recvmsg(3)>>|receive a message
+|<<nng_recvmsg#,nng_recvmsg(3)>>|receive a message
 |<<nng_sendmsg#,nng_sendmsg(3)>>|send a message
 |===
 
diff --git a/docs/man/nng_recvmsg.adoc b/docs/man/nng_recvmsg.adoc
new file mode 100644
index 00000000..03cc99b2
--- /dev/null
+++ b/docs/man/nng_recvmsg.adoc
@@ -0,0 +1,67 @@
+= nng_recvmsg(3)
+//
+// 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
+
+nng_recvmsg - recv message
+
+== SYNOPSIS
+
+[source, c]
+-----------
+#include <nng/nng.h>
+
+int nng_recvmsg(nng_socket s, nng_msg **msgp, int flags);
+-----------
+
+== DESCRIPTION
+
+The `nng_recvmsg()` receives a message on socket _s_, storing the
+received message at the location pointed to by _msgp_.
+
+TIP: Using this function gives access to the message structure, and thus may
+offer more functionality than the simpler <<nng_recv#,nng_recv(3)>> function.
+
+The _flags_ may contain the following value:
+
+`NNG_FLAG_NONBLOCK`::
+  The function returns immediately, even if no message is available.  Without
+  this flag, the function will wait until a message is received by the socket
+  _s_, or any configured timer expires.
+
+NOTE: The semantics of what receiving a message means vary from protocol to
+protocol, so examination of the protocol documentation is encouraged.  (For
+example, with an <<nng_req#,nng_req(7)>> socket a message may only be received
+after a request has been sent, and an <<nng_sub#,nng_sub(7)>> socket
+may only receive messages corresponding to topics to which it has subscribed.)
+Furthermore, some protocols may not support receiving data at all, such as
+<<nng_pub#,nng_pub(7)>>.
+
+== RETURN VALUES
+
+This function returns 0 on success, and non-zero otherwise.
+
+== ERRORS
+
+`NNG_EAGAIN`:: The socket _s_ cannot accept data for sending.
+`NNG_ECLOSED`:: The socket _s_ is not open.
+`NNG_EINVAL`:: An invalid set of _flags_ was specified.
+`NNG_ENOMEM`:: Insufficient memory is available.
+`NNG_ENOTSUP`:: The protocol for socket _s_ does not support receiving.
+`NNG_ESTATE`:: The socket _s_ cannot receive data in this state.
+
+== SEE ALSO
+
+<<nng_msg_free#,nng_msg_free(3)>>,
+<<nng_recv#,nng_recv(3)>>,
+<<nng_sendmsg#,nng_sendmsg(3)>>,
+<<nng_strerror#,nng_strerror(3)>>,
+<<nng#,nng(7)>>
diff --git a/docs/man/nng_sendmsg.adoc b/docs/man/nng_sendmsg.adoc
new file mode 100644
index 00000000..708c1f3b
--- /dev/null
+++ b/docs/man/nng_sendmsg.adoc
@@ -0,0 +1,88 @@
+= nng_sendmsg(3)
+//
+// 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
+
+nng_sendmsg - send message
+
+== SYNOPSIS
+
+[source, c]
+-----------
+#include <nng/nng.h>
+
+int nng_sendmsg(nng_socket s, nng_msg *msg, int flags);
+-----------
+
+== DESCRIPTION
+
+The `nng_sendmsg()` sends message _msg_ using the socket _s_. 
+
+If the function returns zero, indicating it has accepted the message for
+delivery, then the _msg_ is "`owned`" by the socket _s_, and the caller
+must not make any further use of it.  The socket will free the message
+when it is finished.
+
+If the function returns non-zero, then it is the caller's responsibility
+to dispose of the _msg_, which may include freeing it, sending it to
+another socket, or simply trying again later.
+
+TIP: Using this function gives access to the message structure, and may
+offer more functionality than the simpler <<nng_send#,nng_send(3)>> function.
+
+NOTE: The semantics of what sending a message means vary from protocol to
+protocol, so examination of the protocol documentation is encouraged.  (For
+example, with an <<nng_pub#,nng_pub(7)>> socket the data is broadcast, so that
+any peers who have a suitable subscription will be able to receive it using
+<<nng_recv#,nng_recv(3)>> or a similar function.)  Furthermore, some protocols
+may not support sending (such as <<nng_sub#,nng_sub(7)>>) or may
+require other conditions.  (For example, <<nng_rep#,nng_rep(7)>> sockets
+cannot normally send data, which are responses to requests, until they have
+first received a request.)
+
+The _flags_ may contain the following value:
+
+`NNG_FLAG_NONBLOCK`::
+    The function returns immediately, regardless of whether
+    the socket is able to accept the data or not.  If the socket is unable
+    to accept the data (such as if backpressure exists because the peers
+    are consuming messages too slowly, or no peer is present), then the
+    function will return with `NNG_EAGAIN`.  If this flag is not specified,
+    then the function will block if such a condition exists.
+
+
+NOTE: Regardless of the presence or absence of `NNG_FLAG_NONBLOCK`, there may
+be queues between the sender and the receiver.  Furthermore, there is no
+guarantee that the message has actually been delivered.  Finally, with some
+protocols, the semantic is implictly `NNG_FLAG_NONBLOCK`, such as with
+<<nng_pub#,nng_pub(7)>> sockets, which are best-effort delivery only.
+
+== RETURN VALUES
+
+This function returns 0 on success, and non-zero otherwise.
+
+== ERRORS
+
+`NNG_EAGAIN`:: The socket _s_ cannot accept data for sending.
+`NNG_ECLOSED`:: The socket _s_ is not open.
+`NNG_EINVAL`:: An invalid set of _flags_ was specified.
+`NNG_EMSGSIZE`:: The value of _size_ is too large.
+`NNG_ENOMEM`:: Insufficient memory is available.
+`NNG_ENOTSUP`:: The protocol for socket _s_ does not support sending.
+`NNG_ESTATE`:: The socket _s_ cannot send data in this state.
+
+== SEE ALSO
+
+<<nng_msg_alloc#,nng_msg_alloc(3)>>,
+<<nng_recvmsg#,nng_recvmsg(3)>>,
+<<nng_send#,nng_send(3)>>,
+<<nng_strerror#,nng_strerror(3)>>,
+<<nng#,nng(7)>>