= nng_recvmsg(3) // // Copyright 2018 Staysail Systems, Inc. // Copyright 2018 Capitar IT Group BV // // 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 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 <> 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 <> socket a message may only be received after a request has been sent, and an <> 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 <>. == 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 <>, <>, <>, <>, <>