#include <unistd.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <string.h>
#include <stdio.h>

int main(int argc, char **argv)
{
	int fd = open(argv[1], O_RDWR | O_CREAT, (mode_t)0600);
	const char *text = "hello";
	size_t textsize = strlen(text) + 1;
	char *map;

	lseek(fd, textsize-1, SEEK_SET);
	write(fd, "", 1);

	map = mmap(0, textsize, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
	printf("address is 0x%x\n", (unsigned long)map);

	memcpy(map, text, strlen(text));

	//while(1);

	msync(map, textsize, MS_SYNC);
	munmap(map, textsize);

	close(fd);
	return 0;
}