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Beware $? and END

by Felonious (Chaplain)
on Apr 27, 2002 at 16:51 UTC ( #162532=perlmeditation: print w/replies, xml ) Need Help??

Recently, I was bitten by a subtle bug. I had a script that I needed to return a value from to indicate success or failure. Simply enough, where I wanted to fail, I used "exit 1". The problem was that my script always returned success. After alot of frustration, it finally hit me what the problem was...
sub END { system("./dosomething"); } exit 1;
exit() will set $? to the supplied value then eventually terminate with that value, but not until it executes the code in the END block. If anything in there sets $? (as system does), it will overwrite the value set by exit. The solution is to make $? local in the END block.
sub END { local $?; system("./dosomething"); }

-- O thievish Night, Why should'st thou, but for some felonious end, In thy dark lantern thus close up the stars? --Milton

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