#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>
 
#include <deque>
 
#define MAX_LINE_LEN 1024
 
struct Poller
{
	typedef std::deque<char *> LinesType;
	typedef LinesType::const_iterator LinesTypeIterator;
	typedef std::pair<LinesTypeIterator, LinesTypeIterator> LinesTypeIterators;
 
	LinesType lines;
 
	~Poller()
	{
		for (LinesType::iterator i = lines.begin();
			 i != lines.end();
			 i++) {
			free(*i);
		}
	}
 
	LinesTypeIterators
	poll(FILE *f)
	{
		int size = lines.size();
 
		char buf[MAX_LINE_LEN];
		while (true) {
			if (NULL == fgets(buf, MAX_LINE_LEN, f)) break;
			lines.push_back(strdup(buf));
		}
 
		return LinesTypeIterators(lines.begin() + size, lines.end());
	}
};
 
int
main(int argc, char **argv)
{
	FILE *f = fopen(argv[1], "r");
	if (!f) return 1;
 
	Poller poller;
	for (int c = 0; c < 10; c++) {
		Poller::LinesTypeIterators ij = poller.poll(f);
		for (Poller::LinesTypeIterator i = ij.first;
			 i != ij.second;
			 i++) {
			printf("%s", *i);
		}
 
		sleep(1);
	}
 
	printf("All lines:\n");
	for (Poller::LinesType::iterator i = poller.lines.begin();
		 i != poller.lines.end();
		 i++) {
		printf("%s", *i);
	}
 
	fclose(f);
 
	return 0;
}