顯式模板實例化

我正在嘗試僅使用顯式模板實例進行編譯。顯式模板實例化

考慮這個虛擬片斷

#include <vector> 

template struct std::allocator<int>; 
template struct std::vector<int, std::allocator<int>>; 

void fun(){ 
    std::vector<int> v; 
} 

int main(){ 
    fun(); 
};

我想與

g++ -std=c++11 -fno-implicit-templates fun.cc

我預計這個工作編譯它，但是它抱怨解析引用到std::vector成員函數。不應該將成員函數與std::vector類一起自動實例化嗎？我怎樣才能使它工作？

編譯器錯誤是：

/tmp/cc1QxQUn.o: In function `std::vector<int, std::allocator<int> >::push_back(int const&)': 
vec.cc:(.text._ZNSt6vectorIiSaIiEE9push_backERKi[_ZNSt6vectorIiSaIiEE9push_backERKi]+0x65): undefined reference to `void std::vector<int, std::allocator<int> >::_M_emplace_back_aux<int const&>(int const&)' 
/tmp/cc1QxQUn.o: In function `std::vector<int, std::allocator<int> >::push_back(int&&)': 
vec.cc:(.text._ZNSt6vectorIiSaIiEE9push_backEOi[_ZNSt6vectorIiSaIiEE9push_backEOi]+0x2a): undefined reference to `void std::vector<int, std::allocator<int> >::emplace_back<int>(int&&)' 
/tmp/cc1QxQUn.o: In function `std::vector<int, std::allocator<int> >::insert(__gnu_cxx::__normal_iterator<int const*, std::vector<int, std::allocator<int> > >, int const&)': 
vec.cc:(.text._ZNSt6vectorIiSaIiEE6insertEN9__gnu_cxx17__normal_iteratorIPKiS1_EERS4_[_ZNSt6vectorIiSaIiEE6insertEN9__gnu_cxx17__normal_iteratorIPKiS1_EERS4_]+0x14d): undefined reference to `void std::vector<int, std::allocator<int> >::_M_insert_aux<int>(__gnu_cxx::__normal_iterator<int*, std::vector<int, std::allocator<int> > >, int&&)' 
vec.cc:(.text._ZNSt6vectorIiSaIiEE6insertEN9__gnu_cxx17__normal_iteratorIPKiS1_EERS4_[_ZNSt6vectorIiSaIiEE6insertEN9__gnu_cxx17__normal_iteratorIPKiS1_EERS4_]+0x166): undefined reference to `void std::vector<int, std::allocator<int> >::_M_insert_aux<int const&>(__gnu_cxx::__normal_iterator<int*, std::vector<int, std::allocator<int> > >, int const&)' 
/tmp/cc1QxQUn.o: In function `std::vector<int, std::allocator<int> >::insert(__gnu_cxx::__normal_iterator<int const*, std::vector<int, std::allocator<int> > >, int&&)': 
vec.cc:(.text._ZNSt6vectorIiSaIiEE6insertEN9__gnu_cxx17__normal_iteratorIPKiS1_EEOi[_ZNSt6vectorIiSaIiEE6insertEN9__gnu_cxx17__normal_iteratorIPKiS1_EEOi]+0x32): undefined reference to `__gnu_cxx::__normal_iterator<int*, std::vector<int, std::allocator<int> > > std::vector<int, std::allocator<int> >::emplace<int>(__gnu_cxx::__normal_iterator<int const*, std::vector<int, std::allocator<int> > >, int&&)' 
/tmp/cc1QxQUn.o: In function `void std::vector<int, std::allocator<int> >::_M_assign_dispatch<int const*>(int const*, int const*, std::__false_type)': 
vec.cc:(.text._ZNSt6vectorIiSaIiEE18_M_assign_dispatchIPKiEEvT_S5_St12__false_type[_ZNSt6vectorIiSaIiEE18_M_assign_dispatchIPKiEEvT_S5_St12__false_type]+0x2d): undefined reference to `void std::vector<int, std::allocator<int> >::_M_assign_aux<int const*>(int const*, int const*, std::forward_iterator_tag)' 
/tmp/cc1QxQUn.o: In function `void std::vector<int, std::allocator<int> >::_M_insert_dispatch<int const*>(__gnu_cxx::__normal_iterator<int*, std::vector<int, std::allocator<int> > >, int const*, int const*, std::__false_type)': 
vec.cc:(.text._ZNSt6vectorIiSaIiEE18_M_insert_dispatchIPKiEEvN9__gnu_cxx17__normal_iteratorIPiS1_EET_S9_St12__false_type[_ZNSt6vectorIiSaIiEE18_M_insert_dispatchIPKiEEvN9__gnu_cxx17__normal_iteratorIPiS1_EET_S9_St12__false_type]+0x32): undefined reference to `void std::vector<int, std::allocator<int> >::_M_range_insert<int const*>(__gnu_cxx::__normal_iterator<int*, std::vector<int, std::allocator<int> > >, int const*, int const*, std::forward_iterator_tag)' 
/tmp/cc1QxQUn.o: In function `void std::vector<int, std::allocator<int> >::_M_assign_dispatch<std::move_iterator<__gnu_cxx::__normal_iterator<int*, std::vector<int, std::allocator<int> > > > >(std::move_iterator<__gnu_cxx::__normal_iterator<int*, std::vector<int, std::allocator<int> > > >, std::move_iterator<__gnu_cxx::__normal_iterator<int*, std::vector<int, std::allocator<int> > > >, std::__false_type)': 
vec.cc:(.text._ZNSt6vectorIiSaIiEE18_M_assign_dispatchISt13move_iteratorIN9__gnu_cxx17__normal_iteratorIPiS1_EEEEEvT_S9_St12__false_type[_ZNSt6vectorIiSaIiEE18_M_assign_dispatchISt13move_iteratorIN9__gnu_cxx17__normal_iteratorIPiS1_EEEEEvT_S9_St12__false_type]+0x2d): undefined reference to `void std::vector<int, std::allocator<int> >::_M_assign_aux<std::move_iterator<__gnu_cxx::__normal_iterator<int*, std::vector<int, std::allocator<int> > > > >(std::move_iterator<__gnu_cxx::__normal_iterator<int*, std::vector<int, std::allocator<int> > > >, std::move_iterator<__gnu_cxx::__normal_iterator<int*, std::vector<int, std::allocator<int> > > >, std::forward_iterator_tag)' 
collect2: error: ld returned 1 exit status

來源

2015-10-08 PSkocik

從[temp.explicit]：

的顯式實例名稱類模板特也是同類型的顯式實例（聲明或定義）（不包括成員繼承自基地類和成員是模板）除了如下所述之外，先前並未明確專門用於包含明確實例化的翻譯單元。

所以，當你明確實例std::vector<int>，你沒有任何實例化其成員函數模板 - 所以你得到所有這些的未定義的引用（例如_M_emplace_back_aux是一個函數模板）。你必須明確地添加所有這些：

template void std::vector<int>::_M_emplace_back_aux<int>(int&&); 
template void std::vector<int>::_M_emplace_back_aux<const int&>(const int&); 
template void std::vector<int>::_M_assign_aux<int const*>(int const*, int const*, std::forward_iterator_tag); 
...

或者 - 讓隱式實例化只是做它的事情。

來源

2015-10-08 17:03:23 Barry

顯式模板實例化

回答

相關問題