수다닷컴

main()
{
FILE *fp;
char line[512];
fp = fopen(data.txt, r);
fgets(line, 512, fp);
fprintf(stderr, before fork: %s, line);
if (fork() 0) { /* parent process */
sleep(3);
fgets(line, 512, fp);
fprintf(stderr, parent process: %s, line);
}
else { /* child process */
fgets(line, 512, fp);
fprintf(stderr, child process: %s, line);
}
fgets(line, 512, fp);
fprintf(stderr, after fork: %s, line);
}

-------------------------------------------------------
data.txt

Hello My World 1
Hello My World 2
Hello My World 3
Hello My World 4
Hello My World 5
Hello My World 6
Hello My World 7
-------------------------------------------------------
출력
before fork: Hello my world 1
child process: Hello my world 2
after fork: Hello my world 3
parent process: Hello my world 2
after fork: Hello my world 3
-------------------------------------------------------

child, parent가 offset공유하는데, fopen결과가 중복되어 출력이 되는 이유가뭔가요??

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