NAME

       nng_rep - reply protocol

SYNOPSIS

           #include <nng/protocol/reqrep0/rep.h>

DESCRIPTION

       The rep protocol is one half of a request/reply pattern. In this pattern, a requester
       sends a message to one replier, who is expected to reply. The request is resent if no
       reply arrives, until a reply is received or the request times out.

           Tip
           This protocol is useful in setting up RPC-like services. It is also reliable, in that
           a requester will keep retrying until a reply is received.

       The rep protocol is the replier side, and the req protocol is the requester side.

   Socket Operations
       The nng_rep0_open() functions create a replier socket. This socket may be used to receive
       messages (requests), and then to send replies.

       Generally a reply can only be sent after receiving a request.

       Send operations will result in NNG_ESTATE if no corresponding request was previously
       received.

       Likewise, only one receive operation may be pending at a time. Any additional concurrent
       receive operations will result in NNG_ESTATE.

       Raw mode sockets ignore all these restrictions.

   Context Operations
       This protocol supports the creation of contexts for concurrent use cases using
       nng_ctx_open().

       Each context may have at most one outstanding request, and operates independently of the
       others. The restrictions for order of operations with sockets apply equally well for
       contexts, except that each context will be treated as if it were a separate socket.

   Protocol Versions
       Only version 0 of this protocol is supported. (At the time of writing, no other versions
       of this protocol have been defined.)

   Protocol Options
       The rep protocol has no protocol-specific options.

   Protocol Headers
       The rep protocol uses a backtrace in the header. This is more fully documented in the req
       manual.

SEE ALSO

       nng_rep_open(3), nng(7), nng_req(7)

                                            2024-10-11                                 NNG_REP(7)