Re: [Boston.pm] Fwd: script works ok on command line, hangs when run from shell script

Bill Ricker <[email protected]> writes:
> $| won't
> ​do what you want.
>
> perldoc -v '$|'
>
> HANDLE->autoflush( EXPR )
> $OUTPUT_AUTOFLUSH
> $|
>
> If set to nonzero, forces a flush right away and after every write or print
> on the currently selected output channel. Default is 0 (regardless of
> whether the channel is really buffered by the system or not; $| tells you
> only whether you've asked Perl explicitly to flush after each write).
> STDOUT will typically be line buffered if output is to the terminal and
> block buffered otherwise. Setting this variable is useful primarily when
> you are outputting to a pipe or socket, such as when you are running a Perl
> program under rsh and want to see the output as it's happening. This has no
> effect on input buffering. See getc for that. See select on how to select
> the output channel. See also IO::Handle.
>
> Mnemonic: when you want your pipes to be piping hot.
>
> ​ If you want actual non-blocking output in an output pipe or to a file, I
> _think_ you'll need
> ​
> perldoc IO::Handle
>
> ​*$io->blocking ( [ BOOL ] )*
>
> If called with an argument blocking will turn on non-blocking IO if BOOL is
> false, and turn it off if BOOL is true.

I thought he just wanted not to have the output block buffered. Isn't
this orthogonal to that? I.e. non-blocking output eq asynchonous output.
I.e. his script would carry on after a write but output still won't come
out the other end of the c library's buffer until Perl gives it a
block's worth?

-- 
Mike Small
[email protected]

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