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POruby win32api & structs (VerQueryValue)
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copied!<p>I am trying to call the standard Win32 API functions to get file version info, using the <a href="http://rubyforge.org/projects/win32utils/" rel="nofollow noreferrer">win32-api library</a>. </p> <p>The 3 version.dll functions are GetFileVersionInfoSize, GetFileVersionInfo, and VerQueryValue. Then I call RtlMoveMemory in kernel32.dll to get a copy of the VS_FIXEDFILEINFO struct (see Microsoft documentation: <code>http://msdn.microsoft.com/en-us/library/ms646997%28VS.85%29.aspx</code>). </p> <p>I drew from an example I saw using VB: <code>http://support.microsoft.com/kb/139491</code>.</p> <p>My problem is that the data that finally gets returned doesn't seem to match the expected struct, in fact it doesn't even return a consistent value. I suspect the data is getting mangled at some point, probably in VerQueryValue or RtlMoveMemory.</p> <p>Here is the code:</p> <pre><code>GetFileVersionInfoSize = Win32::API.new('GetFileVersionInfoSize','PP','I','version.dll') GetFileVersionInfo = Win32::API.new('GetFileVersionInfo','PIIP','I', 'version.dll') VerQueryValue = Win32::API.new('VerQueryValue','PPPP','I', 'version.dll') RtlMoveMemory = Win32::API.new('RtlMoveMemory', 'PPI', 'V', 'kernel32.dll') buf = [0].pack('L') version_size = GetFileVersionInfoSize.call(myfile + "\0", buf) raise Exception.new if version_size == 0 #TODO version_info = 0.chr * version_size version_ok = GetFileVersionInfo.call(file, 0, version_size, version_info) raise Exception.new if version_ok == 0 #TODO addr = [0].pack('L') size = [0].pack('L') query_ok = VerQueryValue.call(version_info, "\\\0", addr, size) raise Exception.new if query_ok == 0 #TODO # note that at this point, size == 4 -- is that right? fixed_info = Array.new(13,0).pack('L*') RtlMoveMemory.call(fixed_info, addr, fixed_info.length) # fixed_info.unpack('L*') #=> seemingly random data, usually only the first two dwords' worth and the rest 0. </code></pre>

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