rwlock.h

SMS gateway. SMS protocol for CHINA mobile, unicom, lingtong. Using mysql to exchange message.

// *********************************************************************
//
//  Filename:  RWLock.H
//  Functionality: Locking mechanism for concurrent read/write 
//  operations with different processes.
//  It allows a resource (file) to be accessed by multiple readers in
//  shared mode but only one writer in exclusive mode.
//  The lock file is the filename root with extension RWLock
//
// *********************************************************************

#ifndef RWLOCK_H
#define RWLOCK_H
#include <fstream.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/stat.h>

class RWLock {

private:
  int LockIn();
  int LockOut();
  int ResetLock();

  int Readers;
  int Writers;
  unsigned int RWsleep;
  fstream lockFile;
  char *RWLockFileName;

public:
  RWLock() {};
  ~RWLock() {}
  int InitLock( char*, unsigned int );
  int ReadLock();
  int ReadUnLock();
  int WriteLock();
  int WriteUnLock();
};


#endif