I have a new situation which appears to have arrived after an upgrade to debian buster.

I have some scripts in which system(...) is used to call other perl scripts, and those scripts are calling exit explicitly and so should be returning a zero exit code (once >>8 is applied to the value returned by system).

The expected behaviour almost always happens.

However in some cases the exit code returned by system is 1 - and I've been unable to either reliably reproduce the behaviour (it just happens sometimes in processes running on the server) nor stop it happening.

I know that the $CHILD_ERROR / $? perl variable can be used to change the exit code from a process - eg from the perl docs on perlvar:

END {
    $? = 1 if $? == 255;  # die would make it 255
}

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And I've looked high and low for any code (or modules used) which are doing this and have not found any.

So my question is this! Why would the perl have started doing this (I've not been able to find a known bug), and has anyone else started seeing system() >> 8 returning 1 unexpectedly?

In reply to system >> 8 is non-zero when child exits with exit(0) by bjdean

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