You can check condition "error EFOO is the case" via the %! magic hash: 
if ($!{EWOULDBLOCK} ) {
    # would block
};

[download]
Search for %ERRNO in perldoc perlvar.

In reply to Re: Testing $! when use strict is in effect by Dallaylaen
in thread Testing $! when use strict is in effect by Bloehdian

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