Re: [perl-win32-gui-users] Interpreting an lParam pointer

[Len W. <le...@we...>]

perl-win32-gui-users list,<br /><br />I wrote:<br />&gt; But how do I find and read the [COPYDATASTRUCT] structure pointed <br />&gt;&nbsp;&nbsp;&nbsp; to by the integer $lParam ?<br /><br />Well, I figured it out.<br />Here's a sub, not completely general, but handles the case<br />of a scalar message string.<br /><br />Thanks for your indulgence.<br />(Maybe this will be useful for someone else searching the list archive.)<br /><br />Cheers,<br />-Len<br /><br />use Tie::Array::Pointer ;<br /><br />sub read_COPYDATASTRUCT {<br />&nbsp;&nbsp; ## input: $CopyData_p&nbsp;&nbsp; (eg from an lParam)<br />&nbsp;&nbsp; ## output (scalar): $Msg&nbsp;&nbsp;&nbsp; (list): ($Msg, dwData_p)<br />&nbsp;&nbsp; my $CopyData_p = shift ;<br /><br />&nbsp;&nbsp; my @CopyData_a ;<br />&nbsp;&nbsp; tie @CopyData_a, 'Tie::Array::Pointer',<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; {length =&gt; 3,&nbsp;&nbsp;&nbsp; type&nbsp;&nbsp; =&gt; 'L',&nbsp;&nbsp;&nbsp; address =&gt; $CopyData_p } ;<br />&nbsp;&nbsp; my ($dwData_p, $cbData_len, $lpData_p) = @CopyData_a ;<br /><br />&nbsp;&nbsp; my @Msg_a ;<br />&nbsp;&nbsp; tie @Msg_a, 'Tie::Array::Pointer',<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; {length =&gt; $cbData_len,&nbsp; type&nbsp;&nbsp; =&gt; 'C',&nbsp; address =&gt; $lpData_p } ;<br /><br />&nbsp;&nbsp; pop @Msg_a if @Msg_a[-1] eq "\0" ;&nbsp;&nbsp;&nbsp; ## pop off trailing null&nbsp;&nbsp; (more??)<br />&nbsp;&nbsp; my $Msg = pack "C$#Msg_a", @Msg_a ;<br />&nbsp;&nbsp; wantarray ? ($Msg, $dwData_p)&nbsp; : $Msg ;<br />}<br /><br /><br /><br />
<p>On Jul 17, 2009, <strong>le...@we...</strong> wrote:</p>
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<blockquote class="email_quote" style="border-left: 2px solid #267fdb; margin: 0pt 0pt 0pt 1.8ex; padding-left: 1ex;">I am trying to use Win32::GUI from a Perl/Tk program<br />to receive and interpret a message sent from another window.<br /><br />I have successfully set up a window to receive and a hook to<br />&nbsp;&nbsp; handle the message.<br />&nbsp;&nbsp; Using the example in Win32::GUI::Reference/Methods.pod, I have<br /><br />&nbsp;sub msg_handler {<br />&nbsp;&nbsp;&nbsp; ($object, $wParam, $lParam, $type, $msgcode) = @_;<br />&nbsp;&nbsp;&nbsp; print "Click handler called!\n";<br />&nbsp;}<br /><br />The result looks reasonable in the debugger, <br />and $lParam is supposed to be a pointer to a WM_COPYDATA structure.<br /><br />But how do I find and read the structure pointed to by the integer $lParam ?<br />I have a hunch that Win32::API::Struct could help, but I don't quite see how.<br /><br />Thanks,<br />-Len<br /></blockquote>
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