On 11/05/2011 08:07 AM, Ken Peng wrote:
δΊ 2011-11-5 16:57, Uri Guttman ει:
it isn't confusing. when a system call error occurs, you get an undef
return value which says that. then you check $! to see what was the
error. clearing $! on all good calls is a waste of cpu since most calls
succeed vs the number that fail. the same is true for $@ when an eval
fails. you check the return value of the eval and if needed, then check
the value of $@ for what the error was.
Then where did it get the error and set up the value of $! in my first
post?
i keep telling you, there was no error. as for the value, $! has both a
string and numeric value.
perl -le 'print( $! + 0 )'
0
so it was set to 0 like most variables in a program before it is run
(the bss segment of a process if you know what that is). you are just
printing the default value of $! which is meaningless since you
generated no actual error. please get that. there was no error in your
code so you should not print $!. you only check it if you actually got
an error (an undef) from a system call.
uri
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