NAME

       nng_recvmsg - receive a message

SYNOPSIS

           #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() 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 req socket a message may only be received
           after a request has been sent, and an sub 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
           pub.

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_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.

       NNG_ETIMEDOUT
           The operation timed out.

SEE ALSO

       nng_msg_free(3), nng_recv(3), nng_sendmsg(3), nng_strerror(3), nng_socket(5), nng(7)

                                                   2025-02-02                                     NNG_RECVMSG(3)