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    Subjectpid_t range question

    On Linux, type pid_t is defined as an int if you look
    through all the intermediate definitions such as S32_T,
    etc. However, it wraps at 32767, the next value being 300.

    Does anybody know why it doesn't go to 0x7fffffff and
    then wrap to the first unused pid value? I know the
    code "reserves" the first 300 pids. That's not the
    question. I wonder why. Also I see the code setting
    the upper limit as well. I want to know why it is
    set within the range of a short and is not allowed
    to use the full range of an int. Nothing I see in
    the kernel, related to the pid, ever uses a short
    and no 'C' runtime interface limits this either!

    Also, attempts to change /proc/sys/kernel/pid_max fail
    if I attempt to increase it, but I can decrease it
    to where I don't have enough pids available to fork()
    the next command! Is this the correct behavior?

    Dick Johnson
    Penguin : Linux version on an i686 machine (5589.66 BogoMips).
    Warning : 98.36% of all statistics are fiction.

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