I am trying to use log4cpp in my program (*nix machine - Ubuntu 12.10, Codeblocks) to create logs at various instances in the program.

LoggerMain.h

#include "log4cpp/Category.hh"
#include "log4cpp/Appender.hh"
#include "log4cpp/FileAppender.hh"
#include "log4cpp/OstreamAppender.hh"
#include "log4cpp/Layout.hh"
#include "log4cpp/BasicLayout.hh"
#include "log4cpp/Priority.hh"

MainProgram.h

#include "LoggerMain.h"

MainProgram{
public:
log4cpp::Appender *appender;
};

MainProgram.cpp

appender = new log4cpp::FileAppender("default","program.log"); //getting error here
appender->setLayout(new log4cpp::BasicLayout());
log4cpp::Category& root = log4cpp::Category::getRoot();

main{
//will use root here for loggin
}

Error: src/MainProgram.cpp|21|error: ‘appender’ in ‘class MainProgram’ does not name a type|

What's going wrong? I am basically doing the same thing as in the log4cpp simple example documentation here

You can not have operations outside function, put below code into MainProgram construction,

MainProgram::MainProgram(){
  appender = new log4cpp::FileAppender("default","program.log"); //getting error here
  appender->setLayout(new log4cpp::BasicLayout());
  log4cpp::Category& root = log4cpp::Category::getRoot();
}

You could use singleton mode for MainProgram

MainProgram{
public:
   MainProgram* instance(){
     if (!instance){
        instance = new MainProgram();
        return instance;
     }
   }
   MainProgram()
   {
      appender = new new log4cpp::FileAppender("default","program.log"); //getting error here
      appender->setLayout(new log4cpp::BasicLayout());
   }
private:
   log4cpp::Appender *appender;
   MainProgram* instance;
};

int main(int argc, char* argv[])
{
   MainProgram::Instance();
}

Note, C++ supports two forms of main functions, you need to change main function to one of below forms:

int main() { /* ... */ }

int main(int argc, char* argv[]) { /* ... */ }