From 1bcf60a65ee56054e638c0859da1fe2418160bc6 Mon Sep 17 00:00:00 2001 From: Garrett D'Amore Date: Sun, 31 Mar 2024 10:58:17 -0700 Subject: nng_recv* added --- docs/reference/src/sock/nng_sendmsg.3.adoc | 84 ++++++++++++++++++++++++++++++ 1 file changed, 84 insertions(+) create mode 100644 docs/reference/src/sock/nng_sendmsg.3.adoc (limited to 'docs/reference/src/sock/nng_sendmsg.3.adoc') diff --git a/docs/reference/src/sock/nng_sendmsg.3.adoc b/docs/reference/src/sock/nng_sendmsg.3.adoc new file mode 100644 index 00000000..004ae78d --- /dev/null +++ b/docs/reference/src/sock/nng_sendmsg.3.adoc @@ -0,0 +1,84 @@ +# nng_sendmsg + +## NAME + +nng_sendmsg --- send message + +## SYNOPSIS + +``` +#include + +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 xref:nng_send.3.adoc[`nng_send()`] 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 a xref:nng_pub.7.adoc[_pub_] socket the data is broadcast, so that +any peers who have a suitable subscription will be able to receive it using +xref:nng_recv.3.adoc[`nng_recv()`] or a similar function.) +Furthermore, some protocols may not support sending (such as +xref:nng_sub.7.adoc[_sub_]) or may require other conditions. +(For example, xref:nng_rep.7.adoc[_rep_] 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 implicitly `NNG_FLAG_NONBLOCK`, +such as with xref:nng_pub.7.adoc[_pub_] sockets, which are best-effort delivery only. + +## RETURN VALUES + +This function returns 0 on success, and non-zero otherwise. + +## ERRORS + +* `NNG_EAGAIN`: The operation would block, but `NNG_FLAG_NONBLOCK` was specified. +* `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. +* `NNG_ETIMEDOUT`: The operation timed out. + +## SEE ALSO + +[nng_msg_alloc][nng_msg_alloc], +[nng_recvmsg][nng_recvmsg], +[nng_send][nng_send], +[nng_strerror][nng_strerror], +[nng_msg][nng_msg], +[nng_socket][nng_socket], +[nng][nng] + +{{#include ../refs.md}} -- cgit v1.2.3-70-g09d2