clang/test/SemaCXX/libcxx_valarray_hack.cpp

   1 // RUN: %clang_cc1 -fsyntax-only %s -std=c++11 -verify
   2
   3 // This is a test for a hack in Clang that works around an issue with libc++'s
   4 // <valarray> implementation. The <valarray> header contains explicit
   5 // instantiations of functions that it declared with the internal_linkage
   6 // attribute, which are ill-formed by [temp.explicit]p13 (and meaningless).
   7
   8 #ifdef BE_THE_HEADER
   9
  10 #pragma GCC system_header
  11 namespace std {
  12   using size_t = __SIZE_TYPE__;
  13   template<typename T> struct valarray {
  14     __attribute__((internal_linkage)) valarray(size_t) {}
  15     __attribute__((internal_linkage)) ~valarray() {}
  16   };
  17
  18   extern template valarray<size_t>::valarray(size_t);
  19   extern template valarray<size_t>::~valarray();
  20 }
  21
  22 #else
  23
  24 #define BE_THE_HEADER
  25 #include "libcxx_valarray_hack.cpp"
  26
  27 template<typename T> struct foo {
  28   __attribute__((internal_linkage)) void x() {};
  29 };
  30 extern template void foo<int>::x(); // expected-error {{explicit instantiation declaration of 'x' with internal linkage}}
  31
  32 #endif