On Mon, May 11, 2009 at 04:50, Jenda Krynicky <[email protected]> wrote:
> From: Raymond Wan <[email protected]>
>> On Fri, May 8, 2009 at 8:58 PM, John W. Krahn <[email protected]> wrote:
>>
>> >
>> > That depends on the operating system you are using. I use Linux so there
>> > is no difference between "binary" and "text", except for those specific
>> > applications that can't handle "binary" data. If you are on a system like
>> > DOS/Windows then reading or writing "binary" data as "text" will cause
>> > problems because line ending translation occurs with "text" files but not
>> > with "binary" files.
>>
>> I'm on a Linux system too; I guess I've used it for so long, I forgot about
>> the situations when binary/text does matter (i.e., Windows). I see...so it
>> doesn't matter. That would make sense since I just pipe to stdout right
>> now and whether I'm sending "text" [ie., human-readable characters] or not,
>> it all seems to work fine...
>
> Well ... it seems, but it doesn't have to. Based on the locale
> settings, if you do not binmode() the filehandle or open it with the
> right IO layer specified, the stuff you print may undergo some
> charset conversions.
>
> perldoc -f binmode says
>
> On some systems (in general, DOS and Windows-based systems) binmode()
> is necessary when you're not working with a text file. For the sake
> of portability it is a good idea to always use it when appropriate,
> and to never use it when it isn't appropriate. Also, people can set
> their I/O to be by default UTF-8 encoded Unicode, not bytes.
>
> In other words: regardless of platform, use binmode() on binary data,
> like for example images.
snip
or the more modern:
open my $fh, ">:raw", $filename
or die "could not open $filename: $!";
from perldoc perlio[1]
The :raw layer is defined as being identical to calling
binmode($fh) - the stream is made suitable for passing
binary data i.e. each byte is passed as-is. The stream
will still be buffered.
1. http://perldoc.perl.org/PerlIO.html
--
Chas. Owens
wonkden.net
The most important skill a programmer can have is the ability to read.
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