KatolaZ <kato...@freaknet.org> wrote: > Be careful, because conditional expressions in C are subject to > "short-circuiting", meaning that only the minimum number of > expressions sufficient to determine the value of a chain of && and || > will be evaluated. In particular, a chain of || expressions will be > evaluated until there is one that evaluates to TRUE (!=0), while a > chain of && is evaluated until there is one of them which evaluates to > false (==0).
Indeed, and that is the whole point behind using them in this way. I use them a fair bit in shell programming : eg > [ <test expression> ] && something_to_do_if_test_matches instead of > if [ <test expression> ] > then > something_to_do_if_test_matches > fi or even on the command line as in : > apt-get update && apt-get upgrade There can be some situations that can trip you up, eg it might seem clever to do : > some_command && another_command && echo "It worked !" || echo "Failed" While a simple "echo" is unlikely to fail, if that step does fail (eg you are writing status to a file and there's a problem) then you could find both your 'success' and 'fail' commands being run. Used intelligently the && and || operators can both aid readability and improve performance - but equally can be used to obfuscate (either deliberately or accidentally). _______________________________________________ Dng mailing list Dng@lists.dyne.org https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng
