[Dragokas]

Originally Posted by 8guawong how do you know the game engine unhooks after round end?

Originally Posted by Dragokas After hooking it once, engine never unhook it again itself.

Sorry. It was incorrect test. Engine really unhook it automatically on map end as I stated in 1st post (at least in L4D game). Tested on such code:

#include <sourcemod>
#include <sdktools>
#include <sdkhooks>

bool g_bHooked[MAXPLAYERS+1];

public void OnPluginStart()
{
	HookEvent("player_team", Event_Player_Team);
}

void Set_SDKHook(int client)
{
	if (!g_bHooked[client])
	{
		SDKHook(client, SDKHook_OnTakeDamage, OnTakeDamage);
		g_bHooked[client] = true;
	}
}

public Action Event_Player_Team(Event event, char[] name, bool dontBroadcast)
{
	int UserId = event.GetInt("userid");
	if (UserId != 0)
	{
		int client = GetClientOfUserId(UserId);
		if (client != 0)
		{
			int team = event.GetInt("team");
			if (team == 2) // joined to survivor
				Set_SDKHook(client);
		}
	}
}

public Action OnTakeDamage(int victim, int &attacker, int &inflictor, float &damage, int &damagetype, int &weapon, float damageForce[3], float damagePosition[3])
{
	if (GetClientTeam(victim) == 2)
	{
		damage = 0.0;
		return Plugin_Handled;		
	}
	return Plugin_Continue;
}

After vote for new map, damage is taken.

So, considering all recommendations and my wish not to hook every possible clients, my final code will be:

#include <sourcemod>
#include <sdktools>
#include <sdkhooks>

public void OnPluginStart()
{
	HookEvent("player_disconnect", 		Event_PlayerDisconnect);
	HookEvent("player_team", Event_Player_Team);
}

public Action Event_Player_Team(Event event, char[] name, bool dontBroadcast)
{
	int UserId = event.GetInt("userid");
	if (UserId != 0)
	{
		int client = GetClientOfUserId(UserId);
		if (client != 0)
		{
			int team = event.GetInt("team");
			if (team == 2) // joined to survivor
				SDKHook(client, SDKHook_OnTakeDamage, OnTakeDamage);
		}
	}
}

public Action Event_PlayerDisconnect(Event event, char[] name, bool dontBroadcast)
{
	int UserId = event.GetInt("userid");
	if (UserId != 0)
	{
		int client = GetClientOfUserId(UserId);
		if (client != 0)
			SDKUnhook(client, SDKHook_OnTakeDamage, OnTakeDamage);
	}
}

public Action OnTakeDamage(int victim, int &attacker, int &inflictor, float &damage, int &damagetype, int &weapon, float damageForce[3], float damagePosition[3])
{
	if (GetClientTeam(victim) == 2)
	{
		damage = 0.0;
		return Plugin_Handled;		
	}
	return Plugin_Continue;
}

Here, I don't care anymore about flags previously preventing attempt to hook/unhook twice since it looks like it doesn't raise errors.