title: For a RICHEDIT control, what is a character class and what are valid values?
body: <p>From the documentation of <a href="https://docs.microsoft.com/en-us/windows/win32/api/winuser/nc-winuser-editwordbreakproca" rel="nofollow noreferrer">EDITWORDBREAKPROCA callback function</a>:</p>
  
  <blockquote>
    <h1><a href="https://docs.microsoft.com/en-us/windows/win32/api/winuser/nc-winuser-editwordbreakproca#parameters" rel="nofollow noreferrer">Parameters</a></h1>
    
    <p><code>code</code></p>
    
    <p>Type: <strong>int</strong></p>
    
    <p>The action to be taken by the callback function. This parameter can be one of the following values.</p>
    
    <h3>WB_CLASSIFY</h3>
    
    <p>Retrieves the character class and word break flags of the character at the specified position. This value is for use with rich edit controls.</p>
    
    <h1><a href="https://docs.microsoft.com/en-us/windows/win32/api/winuser/nc-winuser-editwordbreakproca#return-value" rel="nofollow noreferrer">Return Value</a></h1>
    
    <p>Type: <strong>int</strong></p>
    
    <p>... If the <em>code</em> parameter specifies <strong>WB_CLASSIFY</strong>, the return value is the character class and word break flags of the character at the specified position. ...
    &nbsp;</p>
  </blockquote>
  
  <p>From the documentation of <a href="https://docs.microsoft.com/en-us/windows/win32/controls/em-findwordbreak" rel="nofollow noreferrer">EM_FINDWORDBREAK message</a>:</p>
  
  <blockquote>
    <h1><a href="https://docs.microsoft.com/en-us/windows/win32/controls/em-findwordbreak#parameters" rel="nofollow noreferrer">Parameters</a></h1>
    
    <p><em>wParam</em></p>
    
    <p>Specifies the find operation. This parameter can be one of the following values.</p>
    
    <h3>WB_CLASSIFY</h3>
    
    <p>Returns the character class and word-break flags of the character at the specified position.</p>
    
    <h1><a href="https://docs.microsoft.com/en-us/windows/win32/controls/em-findwordbreak#return-value" rel="nofollow noreferrer">Return value</a></h1>
    
    <p>The message returns a value based on the <em>wParam</em> parameter.</p>
    
    <h3>WB_CLASSIFY</h3>
    
    <p>Returns the character class and word-break flags of the character at the specified position.</p>
  </blockquote>
  
  <p>My question is what is a character class in this context and what are valid values?  What values are for the flags?  I can't find any information on this anywhere.</p>