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client_server_detection [2019/08/26 20:59] – [How the functions work] korshunclient_server_detection [2019/09/05 23:54] (current) – [Writing robust multiplayer code] korshun
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 </code> </code>
  
-===== How the functions work =====+You can also make sure that a serverside-only function is not called on the client, and a clientside-only function is not called on the server. 
 + 
 +<code> 
 +function ServersideOnlyFunction(void) 
 +
 +    // writing if (IsClient()) would incorrectly display the warning in singleplayer. 
 +    if (!IsServer()) 
 +        printbold(s:"Error: ServersideOnlyFunction was called clientside"); 
 +         
 +    ... 
 +
 + 
 +function ClientsideOnlyFunction(void) 
 +
 +    // writing if (IsServer()) would incorrectly display the warning in singleplayer. 
 +    if (!IsClient()) 
 +        printbold(s:"Error: ClientsideOnlyFunction was called serverside"); 
 +         
 +    ... 
 +
 +</code> 
 + 
 +===== How it works =====
  
 All detection of clients and servers is founded on two functions: [[zdoom>ConsolePlayerNumber]] and [[zan>IsNetworkGame]] (formerly known as ''IsMultiplayer''). All detection of clients and servers is founded on two functions: [[zdoom>ConsolePlayerNumber]] and [[zan>IsNetworkGame]] (formerly known as ''IsMultiplayer'').
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 ''IsClient()'' simply checks if [[zdoom>ConsolePlayerNumber]] is not negative. ''IsClient()'' simply checks if [[zdoom>ConsolePlayerNumber]] is not negative.
  
-''IsServer()'' is more complicated. It returns true if [[zdoom>ConsolePlayerNumber]] is negative. But if it's not negative, it needs to distinguish between multiplayer emulation and real multiplayer. The function needs to return true in multiplayer emulation but false in real multiplayer. +''IsServer()'' is more complicated. It returns true if [[zdoom>ConsolePlayerNumber]] is negative. But if it's not negative, it needs to distinguish between multiplayer emulation and real multiplayer. It checks if the multiplayer is real using [[zan>IsNetworkGame]]. But calling this function in ZDoom/GZDoom crashes the engine. Therefore, before calling ''IsNetworkGame'', it checks if the engine is Zandronum using [[source_port_detection|IsZandronum]].
- +
-It checks if the multiplayer is real using [[zan>IsNetworkGame]]. But calling this function in ZDoom/GZDoom crashes the engine. Therefore, before calling ''IsNetworkGame'', it checks if the engine is Zandronum using [[source_port_detection|IsZandronum]].+
  
-If the engine is not Zandronum, the function returns true, because in ZDoom/GZDoom all players run gameplay code.+If the engine is not Zandronum, the function returns true, because in ZDoom/GZDoom multiplayer all players run gameplay code.
  
-If the engine is Zandronum, the functions returns false if it's real multiplayer, true if it's multiplayer emulation.+If the engine is Zandronum, the function returns false if it's real multiplayer, true if it's multiplayer emulation.
  
 ''IsServerOnly'' and ''IsClientOnly'' simply return ''IsServer() && !IsClient()'' and ''IsClient() && !IsServer()'', respectively. ''IsServerOnly'' and ''IsClientOnly'' simply return ''IsServer() && !IsClient()'' and ''IsClient() && !IsServer()'', respectively.
  
client_server_detection.1566842341.txt.gz · Last modified: 2019/08/26 20:59 by korshun