201 lines
11 KiB
C
201 lines
11 KiB
C
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//====== Copyright Valve Corporation, All rights reserved. ====================
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#ifndef ISTEAMNETWORKINGMESSAGES
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#define ISTEAMNETWORKINGMESSAGES
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#include "steamnetworkingtypes.h"
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#include "steam_api_common.h"
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//-----------------------------------------------------------------------------
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/// The non-connection-oriented interface to send and receive messages
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/// (whether they be "clients" or "servers").
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///
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/// ISteamNetworkingSockets is connection-oriented (like TCP), meaning you
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/// need to listen and connect, and then you send messages using a connection
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/// handle. ISteamNetworkingMessages is more like UDP, in that you can just send
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/// messages to arbitrary peers at any time. The underlying connections are
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/// established implicitly.
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///
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/// Under the hood ISteamNetworkingMessages works on top of the ISteamNetworkingSockets
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/// code, so you get the same routing and messaging efficiency. The difference is
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/// mainly in your responsibility to explicitly establish a connection and
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/// the type of feedback you get about the state of the connection. Both
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/// interfaces can do "P2P" communications, and both support both unreliable
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/// and reliable messages, fragmentation and reassembly.
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///
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/// The primary purpose of this interface is to be "like UDP", so that UDP-based code
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/// can be ported easily to take advantage of relayed connections. If you find
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/// yourself needing more low level information or control, or to be able to better
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/// handle failure, then you probably need to use ISteamNetworkingSockets directly.
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/// Also, note that if your main goal is to obtain a connection between two peers
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/// without concerning yourself with assigning roles of "client" and "server",
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/// you may find the symmetric connection mode of ISteamNetworkingSockets useful.
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/// (See k_ESteamNetworkingConfig_SymmetricConnect.)
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///
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class ISteamNetworkingMessages
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{
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public:
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/// Sends a message to the specified host. If we don't already have a session with that user,
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/// a session is implicitly created. There might be some handshaking that needs to happen
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/// before we can actually begin sending message data. If this handshaking fails and we can't
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/// get through, an error will be posted via the callback SteamNetworkingMessagesSessionFailed_t.
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/// There is no notification when the operation succeeds. (You should have the peer send a reply
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/// for this purpose.)
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///
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/// Sending a message to a host will also implicitly accept any incoming connection from that host.
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///
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/// nSendFlags is a bitmask of k_nSteamNetworkingSend_xxx options
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///
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/// nRemoteChannel is a routing number you can use to help route message to different systems.
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/// You'll have to call ReceiveMessagesOnChannel() with the same channel number in order to retrieve
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/// the data on the other end.
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///
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/// Using different channels to talk to the same user will still use the same underlying
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/// connection, saving on resources. If you don't need this feature, use 0.
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/// Otherwise, small integers are the most efficient.
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///
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/// It is guaranteed that reliable messages to the same host on the same channel
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/// will be be received by the remote host (if they are received at all) exactly once,
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/// and in the same order that they were sent.
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///
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/// NO other order guarantees exist! In particular, unreliable messages may be dropped,
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/// received out of order with respect to each other and with respect to reliable data,
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/// or may be received multiple times. Messages on different channels are *not* guaranteed
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/// to be received in the order they were sent.
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///
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/// A note for those familiar with TCP/IP ports, or converting an existing codebase that
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/// opened multiple sockets: You might notice that there is only one channel, and with
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/// TCP/IP each endpoint has a port number. You can think of the channel number as the
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/// *destination* port. If you need each message to also include a "source port" (so the
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/// recipient can route the reply), then just put that in your message. That is essentially
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/// how UDP works!
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///
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/// Returns:
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/// - k_EREsultOK on success.
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/// - k_EResultNoConnection, if the session has failed or was closed by the peer and
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/// k_nSteamNetworkingSend_AutoRestartBrokenSession was not specified. (You can
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/// use GetSessionConnectionInfo to get the details.) In order to acknowledge the
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/// broken session and start a new one, you must call CloseSessionWithUser, or you may
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/// repeat the call with k_nSteamNetworkingSend_AutoRestartBrokenSession. See
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/// k_nSteamNetworkingSend_AutoRestartBrokenSession for more details.
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/// - See ISteamNetworkingSockets::SendMessageToConnection for more possible return values
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virtual EResult SendMessageToUser( const SteamNetworkingIdentity &identityRemote, const void *pubData, uint32 cubData, int nSendFlags, int nRemoteChannel ) = 0;
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/// Reads the next message that has been sent from another user via SendMessageToUser() on the given channel.
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/// Returns number of messages returned into your list. (0 if no message are available on that channel.)
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///
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/// When you're done with the message object(s), make sure and call SteamNetworkingMessage_t::Release()!
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virtual int ReceiveMessagesOnChannel( int nLocalChannel, SteamNetworkingMessage_t **ppOutMessages, int nMaxMessages ) = 0;
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/// Call this in response to a SteamNetworkingMessagesSessionRequest_t callback.
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/// SteamNetworkingMessagesSessionRequest_t are posted when a user tries to send you a message,
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/// and you haven't tried to talk to them first. If you don't want to talk to them, just ignore
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/// the request. If the user continues to send you messages, SteamNetworkingMessagesSessionRequest_t
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/// callbacks will continue to be posted periodically.
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///
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/// Returns false if there is no session with the user pending or otherwise. If there is an
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/// existing active session, this function will return true, even if it is not pending.
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///
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/// Calling SendMessageToUser() will implicitly accepts any pending session request to that user.
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virtual bool AcceptSessionWithUser( const SteamNetworkingIdentity &identityRemote ) = 0;
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/// Call this when you're done talking to a user to immediately free up resources under-the-hood.
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/// If the remote user tries to send data to you again, another SteamNetworkingMessagesSessionRequest_t
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/// callback will be posted.
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///
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/// Note that sessions that go unused for a few minutes are automatically timed out.
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virtual bool CloseSessionWithUser( const SteamNetworkingIdentity &identityRemote ) = 0;
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/// Call this when you're done talking to a user on a specific channel. Once all
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/// open channels to a user have been closed, the open session to the user will be
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/// closed, and any new data from this user will trigger a
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/// SteamSteamNetworkingMessagesSessionRequest_t callback
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virtual bool CloseChannelWithUser( const SteamNetworkingIdentity &identityRemote, int nLocalChannel ) = 0;
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/// Returns information about the latest state of a connection, if any, with the given peer.
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/// Primarily intended for debugging purposes, but can also be used to get more detailed
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/// failure information. (See SendMessageToUser and k_nSteamNetworkingSend_AutoRestartBrokenSession.)
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///
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/// Returns the value of SteamNetConnectionInfo_t::m_eState, or k_ESteamNetworkingConnectionState_None
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/// if no connection exists with specified peer. You may pass nullptr for either parameter if
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/// you do not need the corresponding details. Note that sessions time out after a while,
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/// so if a connection fails, or SendMessageToUser returns k_EResultNoConnection, you cannot wait
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/// indefinitely to obtain the reason for failure.
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virtual ESteamNetworkingConnectionState GetSessionConnectionInfo( const SteamNetworkingIdentity &identityRemote, SteamNetConnectionInfo_t *pConnectionInfo, SteamNetConnectionRealTimeStatus_t *pQuickStatus ) = 0;
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};
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#define STEAMNETWORKINGMESSAGES_INTERFACE_VERSION "SteamNetworkingMessages002"
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//
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// Callbacks
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//
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#pragma pack( push, 1 )
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/// Posted when a remote host is sending us a message, and we do not already have a session with them
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struct SteamNetworkingMessagesSessionRequest_t
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{
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enum { k_iCallback = k_iSteamNetworkingMessagesCallbacks + 1 };
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SteamNetworkingIdentity m_identityRemote; // user who wants to talk to us
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};
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/// Posted when we fail to establish a connection, or we detect that communications
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/// have been disrupted it an unusual way. There is no notification when a peer proactively
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/// closes the session. ("Closed by peer" is not a concept of UDP-style communications, and
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/// SteamNetworkingMessages is primarily intended to make porting UDP code easy.)
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///
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/// Remember: callbacks are asynchronous. See notes on SendMessageToUser,
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/// and k_nSteamNetworkingSend_AutoRestartBrokenSession in particular.
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///
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/// Also, if a session times out due to inactivity, no callbacks will be posted. The only
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/// way to detect that this is happening is that querying the session state may return
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/// none, connecting, and findingroute again.
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struct SteamNetworkingMessagesSessionFailed_t
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{
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enum { k_iCallback = k_iSteamNetworkingMessagesCallbacks + 2 };
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/// Detailed info about the session that failed.
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/// SteamNetConnectionInfo_t::m_identityRemote indicates who this session
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/// was with.
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SteamNetConnectionInfo_t m_info;
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};
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#pragma pack(pop)
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// Global accessors
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// Using standalone lib
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#ifdef STEAMNETWORKINGSOCKETS_STANDALONELIB
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// Standalone lib.
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static_assert( STEAMNETWORKINGMESSAGES_INTERFACE_VERSION[25] == '2', "Version mismatch" );
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STEAMNETWORKINGSOCKETS_INTERFACE ISteamNetworkingMessages *SteamNetworkingMessages_LibV2();
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inline ISteamNetworkingMessages *SteamNetworkingMessages_Lib() { return SteamNetworkingMessages_LibV2(); }
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// If running in context of steam, we also define a gameserver instance.
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#ifdef STEAMNETWORKINGSOCKETS_STEAM
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STEAMNETWORKINGSOCKETS_INTERFACE ISteamNetworkingMessages *SteamGameServerNetworkingMessages_LibV2();
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inline ISteamNetworkingMessages *SteamGameServerNetworkingMessages_Lib() { return SteamGameServerNetworkingMessages_LibV2(); }
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#endif
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#ifndef STEAMNETWORKINGSOCKETS_STEAMAPI
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inline ISteamNetworkingMessages *SteamNetworkingMessages() { return SteamNetworkingMessages_LibV2(); }
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#ifdef STEAMNETWORKINGSOCKETS_STEAM
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inline ISteamNetworkingMessages *SteamGameServerNetworkingMessages() { return SteamGameServerNetworkingMessages_LibV2(); }
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#endif
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#endif
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#endif
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// Using Steamworks SDK
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#ifdef STEAMNETWORKINGSOCKETS_STEAMAPI
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// Steamworks SDK
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STEAM_DEFINE_USER_INTERFACE_ACCESSOR( ISteamNetworkingMessages *, SteamNetworkingMessages_SteamAPI, STEAMNETWORKINGMESSAGES_INTERFACE_VERSION );
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STEAM_DEFINE_GAMESERVER_INTERFACE_ACCESSOR( ISteamNetworkingMessages *, SteamGameServerNetworkingMessages_SteamAPI, STEAMNETWORKINGMESSAGES_INTERFACE_VERSION );
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#ifndef STEAMNETWORKINGSOCKETS_STANDALONELIB
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inline ISteamNetworkingMessages *SteamNetworkingMessages() { return SteamNetworkingMessages_SteamAPI(); }
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inline ISteamNetworkingMessages *SteamGameServerNetworkingMessages() { return SteamGameServerNetworkingMessages_SteamAPI(); }
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#endif
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#endif
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#endif // ISTEAMNETWORKINGMESSAGES
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