Problem 11.5

#include "csapp.h"

int main()
{
	int fd1, fd2;
	char c;

	fd1 = Open("foobar.txt", O_RDONLY, 0);
	fd2 = Open("foobar.txt", O_RDONLY, 0);
	Read(fd2, &c, 1);
	Dup2(fd2, fd1);
	Read(fd1, &c, 1);
	printf("c = %c\n", c);
	exit(0);
}

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Problem 11.3

int main()
{
	int fd;
	char c;

	fd = Open("foobar.txt", O_RDONLY, 0);
	if (Fork() == 0) {
		Read(fd, &c, 1);
		exit(0);
	}
	Wait(NULL);
	Read(fd, &c, 1);
	printf("c = %c\n", c);
	exit(0);
}

-- What's the output if we remove "Wait(NULL)" ?