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POPInvoke - reading the value of a string field - "Attempted to read or write protected memory"
 

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  1. POPInvoke - reading the value of a string field - "Attempted to read or write protected memory"
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    <p>I'm having trouble accessing the some string fields in a COM interface. Calling the integer fields does not result in an error. When attempting call <code>clientID()</code>, <code>deviceID()</code> or <code>key()</code>, I get the old <em>"Attempted to read or write protected memory"</em> error.</p> <p><strong>Here is the source interface code:</strong> (code sourced from <a href="http://mxr.mozilla.org/mozilla-central/source/netwerk/cache/public/nsICacheVisitor.idl" rel="nofollow noreferrer">here</a>)</p> <pre><code>[scriptable, uuid(fab51c92-95c3-4468-b317-7de4d7588254)] interface nsICacheEntryInfo : nsISupports { readonly attribute string clientID; readonly attribute string deviceID; readonly attribute ACString key; readonly attribute long fetchCount; readonly attribute PRUint32 lastFetched; readonly attribute PRUint32 lastModified; readonly attribute PRUint32 expirationTime; readonly attribute unsigned long dataSize; boolean isStreamBased(); }; </code></pre> <p><strong>Here is the C# code for accessing the interface:</strong></p> <pre><code>[Guid("fab51c92-95c3-4468-b317-7de4d7588254"), ComImport, InterfaceType(ComInterfaceType.InterfaceIsIUnknown)] interface nsICacheEntryInfo { string clientID(); string deviceID(); nsACString key(); int fetchCount(); Int64 lastFetched(); Int64 lastModified(); Int64 expirationTime(); uint dataSize(); [return: MarshalAs(UnmanagedType.Bool)] bool isStreamBased(); } </code></pre> <p>Any suggestions as to why simply trying to read a field should throw access violations at me?</p>
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    1. USNathan Ridley
    1. USNathan Ridley
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      1. USNathan Ridley
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      1. USJustin Grant
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    1. COThe interface has members lastFetched, lastModified, etc as PRUint32. I'm not sure what that is, but it would seem to be 32 bit, yet you are using Int64 in your c# code. Could that be an issue?
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      1. POPInvoke - reading the value of a string field - "Attempted to read or write protected memory"
      1. USChris Dunaway
    2. COI made the change but got the same exception :(
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      1. POPInvoke - reading the value of a string field - "Attempted to read or write protected memory"
      1. USNathan Ridley
    3. COWhat kinds of strings does the C++ code export?
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      1. POPInvoke - reading the value of a string field - "Attempted to read or write protected memory"
      1. USDanny Varod
 

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