#include <stdio.h>

int
main(void)
{
	FILE *f = fopen("duptmp", "w");
	FILE *f1, *f2;
	char line[100];

	if (f == NULL)
		return (1);

	fputs("1\n2\n3\n", f);
	fclose(f);

	f1 = fopen("duptmp", "r");
	if (f1 == NULL)
		return (1);
	f2 = fdopen(dup(fileno(f1)), "r");
	if (f2 == NULL)
		return (2);
	fgets(line, sizeof(line), f1);
	printf("read1: %s", line);
	fgets(line, sizeof(line), f2);
	printf("read2: %s", line);
	return (0);
}