in reply to Script hangs when called via IPC::Open3

I'm trying this on FreeBSD, perl 5.8.8 without theads, and it hangs for me on a different value: somewhere between 15000 and 16000.

But when I move the wait() call to the end of the script, thus below the reading of the handles, it never hangs, not even with a value like 200000 2 million.

I think your buffer space is full, so the writer gets blocked, and wait effectively waits forever, because you never start reading — the writer is blocked forever.

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Re^2: Script hangs when called via IPC::Open3 (Problem)
by ikegami (Patriarch) on Jun 27, 2006 at 22:26 UTC

    That's exactly it. Here's the problem in graphical form, in case it helps: 

    +---------------------+----------------------+
| Parent              | Child                |
+---------------------+----------------------+
| - open3(...);       |                      |
| - wait();           | - ...                |   |
|   - Waits for child | - print 1027;        |   |
|     to end.         | - print 1028;        |   |
|                     | - print 1029;        |   T
|                     | - print 1030;        |   i
|                     | - print 1031;        |   m
|                     |   - Pipe full.       |   e
|                     |     Waits for parent |   |
|                     |     to empty it.     |   |
|                     |                      |   v
| Still waiting...    | Still waiting...     |
+---------------------+----------------------+

    [download]

    When I see open3, I expect to see an IO::Select object.

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