title: Use of undeclared type 'PKCS7' (Receipt-Validation/OpenSSL)
body: <p>To set up Receipt-Validation in my iOS app, I am now following this tutorial:
  <a href="https://www.raywenderlich.com/9257-in-app-purchases-receipt-validation-tutorial" rel="nofollow noreferrer">https://www.raywenderlich.com/9257-in-app-purchases-receipt-validation-tutorial</a>
  and reading at this point: <em>Loading the Receipt.</em></p>
  
  <p>While reading and attempting to understand what is going on I also try to integrate the code in my own app, by doing so getting a hands-on understanding of the process.</p>
  
  <p>Here is one problem I am hitting at this moment:</p>
  
  <p>On this line of code:</p>
  
  <pre><code>private func loadReceipt() -&gt; UnsafeMutablePointer&lt;PKCS7&gt;? {
  </code></pre>
  
  <p>I get this error message:</p>
  
  <pre><code>Use of undeclared type 'PKCS7'
  </code></pre>
  
  <p>After searching the net and trying a few things, I guess it is related to the use of the use of the <em>ReceiptVerifier-Bridging-Header.h</em> file. But I am not sure how to set it in the project.</p>
  
  <p>I will be glad if anyone has some tip allowing me to move forward.
  Thanks in advance!</p>
  
  <p>In case this can be useful, here is the meaningful contents of the bridging header file (ReceiptVerifier-Bridging-Header.h):</p>
  
  <pre><code>#import &lt;openssl/pkcs7.h&gt;
  #import &lt;openssl/objects.h&gt;
  #import &lt;openssl/evp.h&gt;
  #import &lt;openssl/ssl.h&gt;
  #import &lt;openssl/asn1_locl.h&gt;
  </code></pre>