and then the system read is called to fill the buffer again...

You make it sound like Perl launches a thread to fill the buffer in the background. In reality, it's eof that reads from the file.

Move the eof into the eval and the timeout will take effect.

In reply to Re^2: Cannot catch ALRM signal for timeout by ikegami
in thread Cannot catch ALRM signal for timeout by Magice

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