#include <nng/nng.h>
#include <nng/protocol/pubsub0/sub.h>
int nng_sub0_socket_subscribe(nng_socket s, const void *buf, size_t sz);
int nng_sub0_socket_unsubscribe(nng_socket s, const void *buf, size_t sz);
int nng_sub0_ctx_subscribe(nng_ctx c, const void *buf, size_t sz);
int nng_sub0_ctx_unsubscribe(nng_ctx c, const void *buf, size_t sz);nng_sub_subscribe(3)
NAME
nng_sub_subscribe - manage SUB subscriptions
SYNOPSIS
DESCRIPTION
These functions are used to subscribe, or unsubscribe, message topics on either the sub version 0 socket s, or the sub version 0 context c.
Message topics are used to filter messages. The first sz bytes of an incoming message is compared against buf, and if equal the message is accepted and will be available for receiving.
Multiple topics may be registered for the same socket or context, and incoming messages will be forwarded to the application if any of the topics match.
To disable filtering altogether, the buf may be NULL if sz is zero.
In this case, all messages will be forwarded to the application.
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These functions should be used instead of the NNG_OPT_SUB_SUBSCRIBE and
NNG_OPT_SUB_UNSUBSCRIBE options.
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RETURN VALUES
These functions return 0 on success, and non-zero otherwise.
ERRORS
NNG_ENOMEM
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Insufficient memory is available. |
NNG_ENOTSUP
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The protocol is not supported. |
NNG_ENOENT
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The topic is not subscribed. |