That is great information but some of the things stated there are not true.

Slide 4: Trap #1: LOCK_UN
States that "flock FH, LOCK_UN" doesn't flush the buffer -- not true. This may have been the case in older versions of Perl but not in the current ones. From 'perldoc -f flock'
"To avoid the possibility of miscoordination, Perl now flushes FILEHANDLE before locking or unlocking it."

Slide 7: Trap #2: Failing to check for failure
The thing that threw me here is the example. It states that flock() may fail if FH is not open. True. But then it also states that the file will be modified because flock() failed. Not true. How are you going to modify the file if FH is not defined? ;)
The example that should've been there, in my opinion, is the one involving interrupted system calls. If a program is waiting for a lock and it receives a signal, this will result in flock() returning an error and unless the program checks the return value of flock(), it'll happily proceed with its job even though it doesn't really have a lock.

I don't mean to be picky. Please accept this a constructive critisism. :)

--perlplexer

In reply to Re: Re: Question about Flock and die by perlplexer
in thread Question about Flock and die by acarvalh

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