<html>
    <head>
      <base href="https://bugs.llvm.org/">
    </head>
    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - Can not derive from time_get_byname"
   href="https://bugs.llvm.org/show_bug.cgi?id=36353">36353</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>Can not derive from time_get_byname
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>libc++
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>unspecified
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>PC
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>All
          </td>
        </tr>

        <tr>
          <th>Status</th>
          <td>NEW
          </td>
        </tr>

        <tr>
          <th>Severity</th>
          <td>normal
          </td>
        </tr>

        <tr>
          <th>Priority</th>
          <td>P
          </td>
        </tr>

        <tr>
          <th>Component</th>
          <td>All Bugs
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>unassignedclangbugs@nondot.org
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>jasonliu.development@gmail.com
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>llvm-bugs@lists.llvm.org, mclow.lists@gmail.com
          </td>
        </tr></table>
      <p>
        <div>
        <pre>I think this is a valid use case:

#include <locale>
typedef std::char_traits<wchar_t> It;
typedef std::istreambuf_iterator<wchar_t, It> Isit;
struct Mytime : public std::time_get_byname<wchar_t, Isit> {
    Mytime(const char *name, size_t refs)
        : std::time_get_byname<wchar_t, Isit>(name, refs) {}
    };

int main(){
const Mytime t("A",1);
}


When I compile this, I get a bunch of undefined symbols:

  "std::__1::time_get_byname<wchar_t, std::__1::istreambuf_iterator<wchar_t,
std::__1::char_traits<wchar_t> > >::do_date_order() const", referenced from:
      vtable for Mytime in bb-639bbe.o
  "std::__1::time_get_byname<wchar_t, std::__1::istreambuf_iterator<wchar_t,
std::__1::char_traits<wchar_t> > >::__X() const", referenced from:
      vtable for Mytime in bb-639bbe.o
  "std::__1::time_get_byname<wchar_t, std::__1::istreambuf_iterator<wchar_t,
std::__1::char_traits<wchar_t> > >::__c() const", referenced from:
      vtable for Mytime in bb-639bbe.o
  "std::__1::time_get_byname<wchar_t, std::__1::istreambuf_iterator<wchar_t,
std::__1::char_traits<wchar_t> > >::__r() const", referenced from:
      vtable for Mytime in bb-639bbe.o
  "std::__1::time_get_byname<wchar_t, std::__1::istreambuf_iterator<wchar_t,
std::__1::char_traits<wchar_t> > >::__x() const", referenced from:
      vtable for Mytime in bb-639bbe.o
  "std::__1::time_get_byname<wchar_t, std::__1::istreambuf_iterator<wchar_t,
std::__1::char_traits<wchar_t> > >::__am_pm() const", referenced from:
      vtable for Mytime in bb-639bbe.o
  "std::__1::time_get_byname<wchar_t, std::__1::istreambuf_iterator<wchar_t,
std::__1::char_traits<wchar_t> > >::__weeks() const", referenced from:
      vtable for Mytime in bb-639bbe.o
  "std::__1::time_get_byname<wchar_t, std::__1::istreambuf_iterator<wchar_t,
std::__1::char_traits<wchar_t> > >::__months() const", referenced from:
      vtable for Mytime in bb-639bbe.o
  "non-virtual thunk to std::__1::time_get_byname<wchar_t,
std::__1::istreambuf_iterator<wchar_t, std::__1::char_traits<wchar_t> >
<span class="quote">>::__X() const", referenced from:</span >
      vtable for Mytime in bb-639bbe.o
  "non-virtual thunk to std::__1::time_get_byname<wchar_t,
std::__1::istreambuf_iterator<wchar_t, std::__1::char_traits<wchar_t> >
<span class="quote">>::__c() const", referenced from:</span >
      vtable for Mytime in bb-639bbe.o
  "non-virtual thunk to std::__1::time_get_byname<wchar_t,
std::__1::istreambuf_iterator<wchar_t, std::__1::char_traits<wchar_t> >
<span class="quote">>::__r() const", referenced from:</span >
      vtable for Mytime in bb-639bbe.o
  "non-virtual thunk to std::__1::time_get_byname<wchar_t,
std::__1::istreambuf_iterator<wchar_t, std::__1::char_traits<wchar_t> >
<span class="quote">>::__x() const", referenced from:</span >
      vtable for Mytime in bb-639bbe.o
  "non-virtual thunk to std::__1::time_get_byname<wchar_t,
std::__1::istreambuf_iterator<wchar_t, std::__1::char_traits<wchar_t> >
<span class="quote">>::__am_pm() const", referenced from:</span >
      vtable for Mytime in bb-639bbe.o
  "non-virtual thunk to std::__1::time_get_byname<wchar_t,
std::__1::istreambuf_iterator<wchar_t, std::__1::char_traits<wchar_t> >
<span class="quote">>::__weeks() const", referenced from:</span >
      vtable for Mytime in bb-639bbe.o
  "non-virtual thunk to std::__1::time_get_byname<wchar_t,
std::__1::istreambuf_iterator<wchar_t, std::__1::char_traits<wchar_t> >
<span class="quote">>::__months() const", referenced from:</span >
      vtable for Mytime in bb-639bbe.o

When I look at the header and I saw those functions are marked as "always
inline" and "hidden", any reason why those functions are marked as hidden in
the library?</pre>
        </div>
      </p>


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