title: LNK2001 error seen on compiling code in x64 environment. However the code compiles fine in x86 environment
body: <p>I see below linking error on compiling with x64 environment set.</p>
  
  <pre><code>somefile.def : error LNK2001: unresolved external symbol _somesymbol
  somepath\somefile.lib : fatal error LNK1120: 1 unresolved externals
  gmake[2]: *** [somepath\somefile.dll] Error 1120
  </code></pre>
  
  <p><strong>When I checked somefile.def generated in x86, it too had the same above symbol, difference being there it had double underscores ('__somesymbol'). Whats the reason behind this?</strong>
  The code contains both C &amp; C++ files.</p>
  
  <p>Can anyone help in resolving this issue preferably with elaborate explanation?</p>
  
  <p>Thanks</p>