日誌C++庫 log4cpp
安裝: 原始碼安裝 ./configure；make; make check; makeinstall
掌握: layout fileappender category的使用
編譯選項: -llog4cpp -lpthread

執行時，如若提示缺少log4cpp庫檔案，表示找不到log4cpp的動態庫，需要進行以下設定
    以管理員身份登入終端，然後執行以下操作：

    a. # vim /etc/ld.so.conf

    b. 在開啟的檔案末尾新增動態庫log4cpp的路徑(這裡是/usr/local/lib)，然後儲存退出；
       執行命令ldconfig使設定生效即可。
    c. # ldconfig   //更新庫檔案的快取資訊
 

//g++ log4cpp.cc  -llog4cpp -lpthread  -std=c++11

//單例模式下的log4cpp簡單封裝
//log4cpp PatternLayout(定義輸出格式) FileAppender(定義輸出檔案形式)  Category(日誌種類),add 各種型別appender

#include <log4cpp/Category.hh>
#include <log4cpp/Priority.hh>
#include <log4cpp/PatternLayout.hh>
#include <log4cpp/FileAppender.hh>
 

#include <log4cpp/RollingFileAppender.hh>
#include <iostream>
#include <sstream>
#include <string>

using std::cout;
using std::endl;
using std::ostringstream;
using std::string;
using namespace log4cpp;
#define RollingFileName "roll_log4cpp.log"

class Mylog4cpp{
public:
    static
 
 Mylog4cpp * getInstance(){            //單例模式
        if(_instance==NULL)
            _instance = new Mylog4cpp();
        return _instance;
    }
    ~Mylog4cpp();
    void logInfo (const string & Message);    
    void logError(const string & Message);
    void logWarn (const string & Message);
    void logDebug(const string & Message);
private:
    Category & _root;                   //引用避免了再次複製root物件
private:
    static Mylog4cpp * _instance;
    Mylog4cpp();
};

Mylog4cpp * Mylog4cpp::_instance=NULL;          //靜態成員類外初始化

Mylog4cpp::Mylog4cpp()
:_root(Category::getRoot())
{
    PatternLayout * _ptnLyout = new PatternLayout();
    _ptnLyout->setConversionPattern("%d{%Y/%m/%d %H:%M:%S} [%5p] :%m%n");             //PatternLayout定義佈局格式 
    RollingFileAppender * _rollingFileAppender = new RollingFileAppender("rollingFileAppender", RollingFileName,5 * 1024,2) ; //設定回捲格式fileappender
    _rollingFileAppender->setLayout(_ptnLyout);

    _root.addAppender(_rollingFileAppender);   //可以多次add不同型別的appender 實現向不同流輸出
    _root.setPriority(Priority::DEBUG);
}

Mylog4cpp::~Mylog4cpp(){
    //delete _ptnLyout;
    //delete _rollingFileAppender;
    Category::shutdown();
}

void Mylog4cpp::logInfo (const string & Message){
    string Message2=Message;
    Message2 += __FILE__;
    Message2 += ".";
    Message2 += __FUNCTION__;
    Message2 += ".";
    Message2 += std::to_string(__LINE__);
    _root.info(Message2);     
}       
void Mylog4cpp::logError (const string & Message){
    string Message2=Message;
    Message2 += __FILE__;
    Message2 += ".";
    Message2 += __FUNCTION__;
    Message2 += ".";
    Message2 += std::to_string(__LINE__);
    _root.error(Message2);      
}
void Mylog4cpp::logWarn (const string & Message){
    string Message2=Message;
    Message2 += __FILE__;
    Message2 += ".";
    Message2 += __FUNCTION__;
    Message2 += ".";
    Message2 += std::to_string(__LINE__);
    _root.warn(Message2);      
}
void Mylog4cpp::logDebug (const string & Message){
    string Message2=Message;
    Message2 += __FILE__;
    Message2 += ".";
    Message2 += __FUNCTION__;
    Message2 += ".";
    Message2 += std::to_string(__LINE__);   
    _root.debug(Message2);     
}

int main(void)
{
    Mylog4cpp *mylog4cpp1=Mylog4cpp::getInstance();           //單例模式測試
    Mylog4cpp *mylog4cpp2=Mylog4cpp::getInstance();
    Mylog4cpp *mylog4cpp3=Mylog4cpp::getInstance();
    Mylog4cpp *mylog4cpp4=Mylog4cpp::getInstance();
    cout<<"addr1: "<< mylog4cpp1<<endl;
    cout<<"addr1: "<< mylog4cpp2<<endl;
    cout<<"addr1: "<< mylog4cpp3<<endl;
    cout<<"addr1: "<< mylog4cpp4<<endl;

    for(size_t idx = 0; idx != 10; ++idx)
    {
        ostringstream oss;
        oss <<"  "<<__FUNCTION__<<".";
        mylog4cpp1->logInfo(oss.str());
        mylog4cpp2->logError(oss.str());
        mylog4cpp3->logWarn(oss.str());
        mylog4cpp4->logDebug(oss.str());
    }
    return 0;
}