text: #ifndef LOCK_H
  #define LOCK_H
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  #include <stdbool.h>
  
  int lock(
  	int fd, long long start, long long length, bool exclusive,
  	bool immediate
  );
  
  int unlock(int fd, long long start, long long length);
  
  #ifdef __cplusplus
  }
  #endif
  
  #endif
  