Trojan Horses

[Barry Shein]

>I wonder, incidentally, why does close() return something?  Is it just that
>it's a system call?  What checks for close()'s return value?  I could see it
>being used for security checks and such, I suppose (verifying that "fd %d
>had to be closed -- CHECK THIS").

Trying to close a closed file descriptor will cause -1 to be returned
and errno set to EBADF. Close can also be interrupted (EINTR), I would
guess that's most likely to happen with socketio. These are conditions
a program might want to check for, even if (in the first case) just to
check for logic bugs in the program.
-- 
        -Barry Shein

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