title: unresolved external symbol error: not able to solve it
body: <p>I am getting below unresolved external symbol error while compiling the code. I am using third party library. so using third party library namespace while compiling the code.</p>
  
  <blockquote>
    <p>std_uss.obj : error LNK2019: unresolved external symbol "<code>__declspec(dllimport) void __cdecl os_std::os_throw_length_error(void)</code>" (<code>__imp_?os_throw_length_error@os_std@@YAXXZ</code>) referenced in function "<code>private: char * __thiscall os_std::basic_string&lt;char,class os_std::char_traits_char,class os_std::allocator&lt;char&gt; &gt;::allocate(unsigned int)</code>" (<code>?allocate@?$basic_string@DVchar_traits_char@os_std@@V?$allocator@D@2@@os_std@@AAEPADI@Z</code>)</p>
  </blockquote>
  
  <p>I found os_throw_length_error function in one of the files of third part library but did not find any function similar to ::allocator in the code. I did not used standard std namespace since I want compiler to use third party namespace.</p>
  
  <p>If I use <code>using namespace std</code> which is standard then my compilation is successful but then some definitions like string are getting referenced to visual studio string rather than third party string function.</p>