Demostrate how to select a leader from zookeeper in C API, before doing make, set the ZK_DIR environment variable

Makefile

CPP = g++
INCS = -I$(ZK_DIR)/src/c/include -I/home/ochinchina/zookeeper-3.4.6/src/c/generated
LIBS = -L$(ZK_DIR)/src/c/.libs -lzookeeper_mt -lpthread
CXX_FLAGS = -std=c++11

all: leader

leader: ZkLeaderElection.o
	$(CPP) -o leader ZkLeaderElection.o $(LIBS)

.cpp.o:
	$(CPP) -c $(CXX_FLAGS) $(INCS) $<

ZkLeaderElection.cpp

#include <zookeeper.h>
#include <string>
#include <iostream>
#include <unistd.h>

class ZkLeaderElection {
public:
	ZkLeaderElection( const std::string& host, const std::string& root, const std::string& nodeName )
	:host_( host ),
	root_( root ),
	nodeName_( nodeName )
	{
		handle_ = zookeeper_init( host_.c_str(), watch, 5*1000, 0, this, 0 );
	}
	
private:
	static void watch( zhandle_t *zh, int type,  int state, const char *path,void *watcherCtx ) {
		ZkLeaderElection* p = (ZkLeaderElection*)watcherCtx;
		
		if( state == ZOO_CONNECTED_STATE ) {
			if( type == ZOO_CHILD_EVENT ) {
				p->checkChildrenChange();
			} else {
				p->createNodes();
			}
		}
	}
	
	void createNodes() {
		Stat stat;		
		if( zoo_exists( handle_, root_.c_str(), false, &stat ) != ZOK ){
			std::cout << root_ << " does not exist" << std::endl;
			zoo_create( handle_, root_.c_str(), "data", 4, &ZOO_OPEN_ACL_UNSAFE, 0, 0, 0 );
		}
		
		std::string path = root_ + "/n_"; 
		
		if( !nodeName_.empty() ) {
			if( zoo_create( handle_, path.c_str(), nodeName_.data(), nodeName_.length(), &ZOO_OPEN_ACL_UNSAFE, ZOO_SEQUENCE|ZOO_EPHEMERAL, 0, 0 ) == ZOK) {
				std::cout << "success to create " << path << std::endl;
			}
		}
		
		checkChildrenChange();
	}
	
	void checkChildrenChange() {
		String_vector children;
		if( zoo_get_children( handle_, root_.c_str(), true, &children ) == ZOK ) {
			if( children.count > 0 ) {
				int min_seq = 0;
				int j = 0;
				
				//find the leader 
				for( int i = 0; i < children.count; i++ ) {
					std::cout << children.data[i] << std::endl;
					int t = ::atoi( &children.data[i][2] );
					if( i == 0 || min_seq > t ) {
						min_seq = t;
						j = i;
					}
				}
									
				//get the data
				std::string path = root_ + "/" + children.data[j];
				std::cout << "leader:" << getNodeData( path ) << std::endl;					
				
			}
			deallocate_String_vector( &children );
		} 
	}
	
	std::string getNodeData( const std::string& path ) {
		char* buf = new char[256];
		int len = 256;
	
		for( ; ; ) {
			Stat stat;
				
			if( zoo_get( handle_, path.c_str(), false, buf, &len, &stat ) == ZOK ) {
				if( stat.dataLength > len ) {
					delete []buf;
					buf = new char[stat.dataLength ];
					len = stat.dataLength;
				} else {
					std::string result( buf, len );
					delete []buf;
					return result;
				}
				
			} else {
				delete []buf;
				return "";
			}
		}
	
	}
		
private:
	std::string host_;
	std::string root_;
	std::string nodeName_;
	zhandle_t* handle_;
};

int main( int argc, char** argv ) {
	ZkLeaderElection leaderElection( "127.0.0.1:2181", "/election", argv[1] );
	
	for( ; ; ) {
		::sleep( 10 );
	}
}

why I get the error 'zoo_exists was not declared in this scope'? The other api such as zoo_create and zoo_get meet the same error.

which project? Sherlockedb <[email protected]> 于2019年8月14日周三 下午9:26写道：

…

why I get the error 'zoo_exists was not declared in this scope'? The other api such as zoo_create and zoo_get meet the same error. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <https://gist.github.com/38e70fc3d8fa457d5cd8?email_source=notifications&email_token=ABKX2TUPYAIW2CUVNF2JKNTQEQBZRA5CNFSM4ILU3YOKYY3PNVWWK3TUL52HS4DFVNDWS43UINXW23LFNZ2KUY3PNVWWK3TUL5UWJTQAFXAIC#gistcomment-2998401>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ABKX2TUKJFGZKGTXCSOWB3DQEQBZRANCNFSM4ILU3YOA> .