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POWhy Win32 error codes don't match method signatures?
 

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  1. POWhy Win32 error codes don't match method signatures?
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    <p>Can someone help me understand why Win32 error codes don't match method signatures and what is the correct way to deal with this issue?</p> <p>Take for example <a href="http://msdn.microsoft.com/en-us/library/windows/desktop/aa379798%28v=vs.85%29.aspx" rel="nofollow">SCardReleaseContext</a>, as per the MSDN documentation the return type is <code>LONG</code>. As per <a href="http://msdn.microsoft.com/en-us/magazine/cc164123.aspx#S6" rel="nofollow">this MSDN article</a>, the c# equivalent of <code>LONG</code> is <code>int</code>. Looking at some p/invoke <a href="http://www.pinvoke.net/default.aspx/winscard.scardreleasecontext" rel="nofollow">example signatures</a> of SCardReleaseContext, the return type is also marked as <code>int</code>.</p> <p>However, the definitions of <a href="http://msdn.microsoft.com/en-us/library/windows/desktop/aa374738%28v=vs.85%29.aspx" rel="nofollow">WinSCard error codes</a>, do not match the <code>int</code> type, because the value simply doesn't fit into <code>int</code>.</p> <p>Currently, in my c# program, I have had to define the return value and the error code values as <code>uint</code>. This way my code compiles and works. Otherwise, the compiler will complain that the value cannot be converted to int, for instance - <code>enum ErrorCodes : int { SCARD_E_CANCELLED = 0x80100002 }</code>.</p> <p>Can I correctly assume that a c++ compiler will take the value 0x80100001 (which doesn't fit into an int), let it overflow and thus turn the value into some appropriate matching negative value?</p> <p>Also, am I correct in saying that the c# compiler will not allow such a mistake/bug/flaw to be written and the correct way of handeling this (corner) case is to purposefully "brake" the p/invoke signature and use <code>uint</code> instead?</p> <p><strong>Edit:</strong><br> Fixed the last link, which was sort of incorrect, in it the values were cast to <code>DWORD</code>, which happens to be <code>uint</code>. Set the link to point to Microsoft's own site.</p>
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