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perl-IO-stringy-2.108-4mdk.noarch.rpm

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  <TITLE>IO::ScalarArray 2.103</TITLE>
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<FONT FACE="sans-serif" SIZE=-1><A HREF="http://www.zeegee.com" TARGET="_top"><IMG SRC="icons/zeegee.gif" ALT="ZeeGee Software" ALIGN="RIGHT" BORDER="0"></A><A NAME="__TOP__"><H1>IO::ScalarArray 2.103</H1>
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<P><B>This module is <FONT COLOR="#990000">BETA</FONT> code, which means that the interfaces are fairly stable BUT it has not been out in the community long enough to guarantee much testing. Use with caution! Please report any errors back to <A HREF="mailto:eryq@zeegee.com">eryq@zeegee.com</A> as soon as you can.</B><UL>
<LI> <A NAME="menu:NAME"><A HREF="#NAME">NAME</A></A>
<LI> <A NAME="menu:SYNOPSIS"><A HREF="#SYNOPSIS">SYNOPSIS</A></A>
<LI> <A NAME="menu:DESCRIPTION"><A HREF="#DESCRIPTION">DESCRIPTION</A></A>
<LI> <A NAME="menu:PUBLIC_INTERFACE"><A HREF="#PUBLIC_INTERFACE">PUBLIC INTERFACE</A></A>
<UL>
<LI> <A NAME="menu:Construction"><A HREF="#Construction">Construction</A></A>
<UL>
<LI> <A NAME="menu:item:new_ARGS"><A HREF="#item:new_ARGS">new [ARGS...]</A></A>
<LI> <A NAME="menu:item:open_ARRAYREF"><A HREF="#item:open_ARRAYREF">open [ARRAYREF]</A></A>
<LI> <A NAME="menu:item:opened"><A HREF="#item:opened">opened</A></A>
<LI> <A NAME="menu:item:close"><A HREF="#item:close">close</A></A>
</UL>
<LI> <A NAME="menu:Input_and_output"><A HREF="#Input_and_output">Input and output</A></A>
<UL>
<LI> <A NAME="menu:item:flush"><A HREF="#item:flush">flush </A></A>
<LI> <A NAME="menu:item:getc"><A HREF="#item:getc">getc</A></A>
<LI> <A NAME="menu:item:getline"><A HREF="#item:getline">getline</A></A>
<LI> <A NAME="menu:item:getlines"><A HREF="#item:getlines">getlines</A></A>
<LI> <A NAME="menu:item:print_ARGS"><A HREF="#item:print_ARGS">print ARGS...</A></A>
<LI> <A NAME="menu:item:read_BUF_NBYTES_OFFSET"><A HREF="#item:read_BUF_NBYTES_OFFSET">read BUF, NBYTES, [OFFSET];</A></A>
<LI> <A NAME="menu:item:write_BUF_NBYTES_OFFSET"><A HREF="#item:write_BUF_NBYTES_OFFSET">write BUF, NBYTES, [OFFSET];</A></A>
</UL>
<LI> <A NAME="menu:Seeking_telling_and_other_attributes"><A HREF="#Seeking_telling_and_other_attributes">Seeking/telling and other attributes</A></A>
<UL>
<LI> <A NAME="menu:item:autoflush"><A HREF="#item:autoflush">autoflush </A></A>
<LI> <A NAME="menu:item:binmode"><A HREF="#item:binmode">binmode</A></A>
<LI> <A NAME="menu:item:clearerr"><A HREF="#item:clearerr">clearerr</A></A>
<LI> <A NAME="menu:item:eof"><A HREF="#item:eof">eof </A></A>
<LI> <A NAME="menu:item:seek_POS_WHENCE"><A HREF="#item:seek_POS_WHENCE">seek POS,WHENCE</A></A>
<LI> <A NAME="menu:item:tell"><A HREF="#item:tell">tell</A></A>
<LI> <A NAME="menu:item:setpos_POS"><A HREF="#item:setpos_POS">setpos POS</A></A>
<LI> <A NAME="menu:item:getpos"><A HREF="#item:getpos">getpos</A></A>
<LI> <A NAME="menu:item:aref"><A HREF="#item:aref">aref</A></A>
</UL>
</UL>
<LI> <A NAME="menu:WARNINGS"><A HREF="#WARNINGS">WARNINGS</A></A>
<LI> <A NAME="menu:VERSION"><A HREF="#VERSION">VERSION</A></A>
<LI> <A NAME="menu:AUTHOR"><A HREF="#AUTHOR">AUTHOR</A></A>
<UL>
<LI> <A NAME="menu:Principal_author"><A HREF="#Principal_author">Principal author</A></A>
<LI> <A NAME="menu:Other_contributors"><A HREF="#Other_contributors">Other contributors</A></A>
</UL>
</UL>


<P><HR>
<A NAME="NAME"><H2><A HREF="#__TOP__"><IMG SRC="icons/h1bullet.gif" ALT="Top" BORDER="0"></A> NAME</H2></A>


<P>IO::ScalarArray - IO:: interface for reading/writing an array of scalars



<P><HR>
<A NAME="SYNOPSIS"><H2><A HREF="#__TOP__"><IMG SRC="icons/h1bullet.gif" ALT="Top" BORDER="0"></A> SYNOPSIS</H2></A>


<P>Perform I/O on strings, using the basic OO interface...

<FONT SIZE=3 FACE="courier"><PRE>
    use IO::ScalarArray;
    @data = (&quot;My mes&quot;, &quot;sage:\n&quot;);
</PRE></FONT>
<FONT SIZE=3 FACE="courier"><PRE>
    ### Open a handle on an array, and append to it:
    $AH = new IO::ScalarArray \@data;
    $AH-&gt;print(&quot;Hello&quot;);       
    $AH-&gt;print(&quot;, world!\nBye now!\n&quot;);  
    print &quot;The array is now: &quot;, @data, &quot;\n&quot;;
</PRE></FONT>
<FONT SIZE=3 FACE="courier"><PRE>
    ### Open a handle on an array, read it line-by-line, then close it:
    $AH = new IO::ScalarArray \@data;
    while (defined($_ = $AH-&gt;getline)) { 
	print &quot;Got line: $_&quot;;
    }
    $AH-&gt;close;
</PRE></FONT>
<FONT SIZE=3 FACE="courier"><PRE>
    ### Open a handle on an array, and slurp in all the lines:
    $AH = new IO::ScalarArray \@data;
    print &quot;All lines:\n&quot;, $AH-&gt;getlines; 
</PRE></FONT>
<FONT SIZE=3 FACE="courier"><PRE>
    ### Get the current position (either of two ways):
    $pos = $AH-&gt;getpos;         
    $offset = $AH-&gt;tell;  
</PRE></FONT>
<FONT SIZE=3 FACE="courier"><PRE>
    ### Set the current position (either of two ways):
    $AH-&gt;setpos($pos);        
    $AH-&gt;seek($offset, 0);
</PRE></FONT>
<FONT SIZE=3 FACE="courier"><PRE>
    ### Open an anonymous temporary array:
    $AH = new IO::ScalarArray;
    $AH-&gt;print(&quot;Hi there!&quot;);
    print &quot;I printed: &quot;, @{$AH-&gt;aref}, &quot;\n&quot;;      ### get at value
</PRE></FONT>

<P>Don't like OO for your I/O?  No problem.  
Thanks to the magic of an invisible tie(), the following now 
works out of the box, just as it does with IO::Handle:
    
    use IO::ScalarArray;
    @data = (&quot;My mes&quot;, &quot;sage:\n&quot;);

<FONT SIZE=3 FACE="courier"><PRE>
    ### Open a handle on an array, and append to it:
    $AH = new IO::ScalarArray \@data;
    print $AH &quot;Hello&quot;;    
    print $AH &quot;, world!\nBye now!\n&quot;;
    print &quot;The array is now: &quot;, @data, &quot;\n&quot;;
</PRE></FONT>
<FONT SIZE=3 FACE="courier"><PRE>
    ### Open a handle on a string, read it line-by-line, then close it:
    $AH = new IO::ScalarArray \@data;
    while (&lt;$AH&gt;) {
	print &quot;Got line: $_&quot;;
    }
    close $AH;
</PRE></FONT>
<FONT SIZE=3 FACE="courier"><PRE>
    ### Open a handle on a string, and slurp in all the lines:
    $AH = new IO::ScalarArray \@data;
    print &quot;All lines:\n&quot;, &lt;$AH&gt;;
</PRE></FONT>
<FONT SIZE=3 FACE="courier"><PRE>
    ### Get the current position (WARNING: requires 5.6):
    $offset = tell $AH;
</PRE></FONT>
<FONT SIZE=3 FACE="courier"><PRE>
    ### Set the current position (WARNING: requires 5.6):
    seek $AH, $offset, 0;
</PRE></FONT>
<FONT SIZE=3 FACE="courier"><PRE>
    ### Open an anonymous temporary scalar:
    $AH = new IO::ScalarArray;
    print $AH &quot;Hi there!&quot;;
    print &quot;I printed: &quot;, @{$AH-&gt;aref}, &quot;\n&quot;;      ### get at value
</PRE></FONT>

<P>And for you folks with 1.x code out there: the old tie() style still works,
though this is <I>unnecessary and deprecated</I>:

<FONT SIZE=3 FACE="courier"><PRE>
    use IO::ScalarArray;
</PRE></FONT>
<FONT SIZE=3 FACE="courier"><PRE>
    ### Writing to a scalar...
    my @a; 
    tie *OUT, 'IO::ScalarArray', \@a;
    print OUT &quot;line 1\nline 2\n&quot;, &quot;line 3\n&quot;;
    print &quot;Array is now: &quot;, @a, &quot;\n&quot;
</PRE></FONT>
<FONT SIZE=3 FACE="courier"><PRE>
    ### Reading and writing an anonymous scalar... 
    tie *OUT, 'IO::ScalarArray';
    print OUT &quot;line 1\nline 2\n&quot;, &quot;line 3\n&quot;;
    tied(OUT)-&gt;seek(0,0);
    while (&lt;OUT&gt;) { 
        print &quot;Got line: &quot;, $_;
    }
</PRE></FONT>


<P><HR>
<A NAME="DESCRIPTION"><H2><A HREF="#__TOP__"><IMG SRC="icons/h1bullet.gif" ALT="Top" BORDER="0"></A> DESCRIPTION</H2></A>


<P>This class is part of the IO::Stringy distribution;
see <A HREF="../IO/Stringy.pm.html">IO::Stringy</A> for change log and general information.


<P>The IO::ScalarArray class implements objects which behave just like 
IO::Handle (or FileHandle) objects, except that you may use them 
to write to (or read from) arrays of scalars.  Logically, an
array of scalars defines an in-core &quot;file&quot; whose contents are
the concatenation of the scalars in the array.  The handles created by 
this class are automatically tiehandle'd (though please see <A HREF="#WARNINGS">WARNINGS</A>
for information relevant to your Perl version).


<P>For writing large amounts of data with individual print() statements, 
this class is likely to be more efficient than IO::Scalar.


<P>Basically, this:

<FONT SIZE=3 FACE="courier"><PRE>
    my @a;
    $AH = new IO::ScalarArray \@a;
    $AH-&gt;print(&quot;Hel&quot;, &quot;lo, &quot;);         ### OO style
    $AH-&gt;print(&quot;world!\n&quot;);            ### ditto
</PRE></FONT>

<P>Or this:

<FONT SIZE=3 FACE="courier"><PRE>
    my @a;
    $AH = new IO::ScalarArray \@a;
    print $AH &quot;Hel&quot;, &quot;lo, &quot;;           ### non-OO style
    print $AH &quot;world!\n&quot;;              ### ditto
</PRE></FONT>

<P>Causes @a to be set to the following array of 3 strings:

<FONT SIZE=3 FACE="courier"><PRE>
    ( &quot;Hel&quot; , 
      &quot;lo, &quot; , 
      &quot;world!\n&quot; )
</PRE></FONT>

<P>See <A HREF="../IO/Scalar.pm.html">IO::Scalar</A> and compare with this class.



<P><HR>
<A NAME="PUBLIC_INTERFACE"><H2><A HREF="#__TOP__"><IMG SRC="icons/h1bullet.gif" ALT="Top" BORDER="0"></A> PUBLIC INTERFACE</H2></A>



<P><HR>
<A NAME="Construction"><H3><A HREF="#__TOP__"><IMG SRC="icons/h2bullet.gif" ALT="Top" BORDER="0"></A> Construction</H3></A>



<DL>
<P><DT><B><A HREF="#__TOP__"><IMG SRC="icons/itembullet.gif" ALT="Top" BORDER="0"></A> <A NAME="item:new"><A NAME="item:new_ARGS">new [ARGS...]</A></A></B></DT>
<DD>
<I>Class method.</I>
Return a new, unattached array handle.  
If any arguments are given, they're sent to open().

<P><DT><B><A HREF="#__TOP__"><IMG SRC="icons/itembullet.gif" ALT="Top" BORDER="0"></A> <A NAME="item:open"><A NAME="item:open_ARRAYREF">open [ARRAYREF]</A></A></B></DT>
<DD>
<I>Instance method.</I>
Open the array handle on a new array, pointed to by ARRAYREF.
If no ARRAYREF is given, a &quot;private&quot; array is created to hold
the file data.


<P>Returns the self object on success, undefined on error.

<P><DT><B><A HREF="#__TOP__"><IMG SRC="icons/itembullet.gif" ALT="Top" BORDER="0"></A> <A NAME="item:opened">opened</A></B></DT>
<DD>
<I>Instance method.</I>
Is the array handle opened on something?

<P><DT><B><A HREF="#__TOP__"><IMG SRC="icons/itembullet.gif" ALT="Top" BORDER="0"></A> <A NAME="item:close">close</A></B></DT>
<DD>
<I>Instance method.</I>
Disassociate the array handle from its underlying array.
Done automatically on destroy.

</DL>



<P><HR>
<A NAME="Input_and_output"><H3><A HREF="#__TOP__"><IMG SRC="icons/h2bullet.gif" ALT="Top" BORDER="0"></A> Input and output</H3></A>



<DL>
<P><DT><B><A HREF="#__TOP__"><IMG SRC="icons/itembullet.gif" ALT="Top" BORDER="0"></A> <A NAME="item:flush">flush</A></B></DT>
<DD>
<I>Instance method.</I>
No-op, provided for OO compatibility.

<P><DT><B><A HREF="#__TOP__"><IMG SRC="icons/itembullet.gif" ALT="Top" BORDER="0"></A> <A NAME="item:getc">getc</A></B></DT>
<DD>
<I>Instance method.</I>
Return the next character, or undef if none remain.
This does a read(1), which is somewhat costly.

<P><DT><B><A HREF="#__TOP__"><IMG SRC="icons/itembullet.gif" ALT="Top" BORDER="0"></A> <A NAME="item:getline">getline</A></B></DT>
<DD>
<I>Instance method.</I>
Return the next line, or undef on end of data.
Can safely be called in an array context.
Currently, lines are delimited by &quot;\n&quot;.

<P><DT><B><A HREF="#__TOP__"><IMG SRC="icons/itembullet.gif" ALT="Top" BORDER="0"></A> <A NAME="item:getlines">getlines</A></B></DT>
<DD>
<I>Instance method.</I>
Get all remaining lines.
It will croak() if accidentally called in a scalar context.

<P><DT><B><A HREF="#__TOP__"><IMG SRC="icons/itembullet.gif" ALT="Top" BORDER="0"></A> <A NAME="item:print"><A NAME="item:print_ARGS">print ARGS...</A></A></B></DT>
<DD>
<I>Instance method.</I>
Print ARGS to the underlying array.  


<P>Currently, this always causes a &quot;seek to the end of the array&quot;
and generates a new array entry.  This may change in the future.

<P><DT><B><A HREF="#__TOP__"><IMG SRC="icons/itembullet.gif" ALT="Top" BORDER="0"></A> <A NAME="item:read"><A NAME="item:read_BUF_NBYTES_OFFSET">read BUF, NBYTES, [OFFSET];</A></A></B></DT>
<DD>
<I>Instance method.</I>
Read some bytes from the array.
Returns the number of bytes actually read, 0 on end-of-file, undef on error.

<P><DT><B><A HREF="#__TOP__"><IMG SRC="icons/itembullet.gif" ALT="Top" BORDER="0"></A> <A NAME="item:write"><A NAME="item:write_BUF_NBYTES_OFFSET">write BUF, NBYTES, [OFFSET];</A></A></B></DT>
<DD>
<I>Instance method.</I>
Write some bytes into the array.

</DL>



<P><HR>
<A NAME="Seeking_telling_and_other_attributes"><H3><A HREF="#__TOP__"><IMG SRC="icons/h2bullet.gif" ALT="Top" BORDER="0"></A> Seeking/telling and other attributes</H3></A>



<DL>
<P><DT><B><A HREF="#__TOP__"><IMG SRC="icons/itembullet.gif" ALT="Top" BORDER="0"></A> <A NAME="item:autoflush">autoflush</A></B></DT>
<DD>
<I>Instance method.</I>
No-op, provided for OO compatibility.

<P><DT><B><A HREF="#__TOP__"><IMG SRC="icons/itembullet.gif" ALT="Top" BORDER="0"></A> <A NAME="item:binmode">binmode</A></B></DT>
<DD>
<I>Instance method.</I>
No-op, provided for OO compatibility.

<P><DT><B><A HREF="#__TOP__"><IMG SRC="icons/itembullet.gif" ALT="Top" BORDER="0"></A> <A NAME="item:clearerr">clearerr</A></B></DT>
<DD>
<I>Instance method.</I>  Clear the error and EOF flags.  A no-op.

<P><DT><B><A HREF="#__TOP__"><IMG SRC="icons/itembullet.gif" ALT="Top" BORDER="0"></A> <A NAME="item:eof">eof</A></B></DT>
<DD>
<I>Instance method.</I>  Are we at end of file?

<P><DT><B><A HREF="#__TOP__"><IMG SRC="icons/itembullet.gif" ALT="Top" BORDER="0"></A> <A NAME="item:seek"><A NAME="item:seek_POS_WHENCE">seek POS,WHENCE</A></A></B></DT>
<DD>
<I>Instance method.</I>
Seek to a given position in the stream.
Only a WHENCE of 0 (SEEK_SET) is supported.

<P><DT><B><A HREF="#__TOP__"><IMG SRC="icons/itembullet.gif" ALT="Top" BORDER="0"></A> <A NAME="item:tell">tell</A></B></DT>
<DD>
<I>Instance method.</I>
Return the current position in the stream, as a numeric offset.

<P><DT><B><A HREF="#__TOP__"><IMG SRC="icons/itembullet.gif" ALT="Top" BORDER="0"></A> <A NAME="item:setpos"><A NAME="item:setpos_POS">setpos POS</A></A></B></DT>
<DD>
<I>Instance method.</I>
Seek to a given position in the array, using the opaque getpos() value.
Don't expect this to be a number.

<P><DT><B><A HREF="#__TOP__"><IMG SRC="icons/itembullet.gif" ALT="Top" BORDER="0"></A> <A NAME="item:getpos">getpos</A></B></DT>
<DD>
<I>Instance method.</I>
Return the current position in the array, as an opaque value.
Don't expect this to be a number.

<P><DT><B><A HREF="#__TOP__"><IMG SRC="icons/itembullet.gif" ALT="Top" BORDER="0"></A> <A NAME="item:aref">aref</A></B></DT>
<DD>
<I>Instance method.</I>
Return a reference to the underlying array.

</DL>



<P><HR>
<A NAME="WARNINGS"><H2><A HREF="#__TOP__"><IMG SRC="icons/h1bullet.gif" ALT="Top" BORDER="0"></A> WARNINGS</H2></A>


<P>Perl's TIEHANDLE spec was incomplete prior to 5.005_57;
it was missing support for <CODE>seek()</CODE>, <CODE>tell()</CODE>, and <CODE>eof()</CODE>.
Attempting to use these functions with an IO::ScalarArray will not work
prior to 5.005_57. IO::ScalarArray will not have the relevant methods 
invoked; and even worse, this kind of bug can lie dormant for a while.
If you turn warnings on (via <CODE>$^W</CODE> or <CODE>perl -w</CODE>),
and you see something like this...

<FONT SIZE=3 FACE="courier"><PRE>
    attempt to seek on unopened filehandle
</PRE></FONT>

<P>...then you are probably trying to use one of these functions
on an IO::ScalarArray with an old Perl.  The remedy is to simply
use the OO version; e.g.:

<FONT SIZE=3 FACE="courier"><PRE>
    $AH-&gt;seek(0,0);    ### GOOD: will work on any 5.005
    seek($AH,0,0);     ### WARNING: will only work on 5.005_57 and beyond
</PRE></FONT>


<P><HR>
<A NAME="VERSION"><H2><A HREF="#__TOP__"><IMG SRC="icons/h1bullet.gif" ALT="Top" BORDER="0"></A> VERSION</H2></A>


<P>$Id: ScalarArray.pm,v 2.103 2001/08/09 08:04:44 eryq Exp $



<P><HR>
<A NAME="AUTHOR"><H2><A HREF="#__TOP__"><IMG SRC="icons/h1bullet.gif" ALT="Top" BORDER="0"></A> AUTHOR</H2></A>



<P><HR>
<A NAME="Principal_author"><H3><A HREF="#__TOP__"><IMG SRC="icons/h2bullet.gif" ALT="Top" BORDER="0"></A> Principal author</H3></A>


<P>Eryq (<I><FILE><A HREF="mailto:eryq@zeegee.com">eryq@zeegee.com</A></FILE></I>).
President, ZeeGee Software Inc (<I><FILE><A HREF="http://www.zeegee.com">http://www.zeegee.com</A></FILE></I>).



<P><HR>
<A NAME="Other_contributors"><H3><A HREF="#__TOP__"><IMG SRC="icons/h2bullet.gif" ALT="Top" BORDER="0"></A> Other contributors</H3></A>


<P>Thanks to the following individuals for their invaluable contributions
(if I've forgotten or misspelled your name, please email me!):


<P><I>Andy Glew,</I>
for suggesting <CODE>getc()</CODE>.


<P><I>Brandon Browning,</I>
for suggesting <CODE>opened()</CODE>.


<P><I>Eric L. Brine,</I>
for his offset-using read() and write() implementations. 


<P><I>Doug Wilson,</I>
for the IO::Handle inheritance and automatic tie-ing.

<P><HR>
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