I am writing a simple code for learning sfinae. However, it generates a warning only in Visual Studio (not when using g++).
The code is:
#include <iostream>
#include <type_traits>
template <class T, typename std::enable_if<std::is_integral<T>::value, nullptr_t>::type = nullptr>
void f(T t)
{
std::cout << "Integer" << std::endl;
return;
}
template <class T, typename std::enable_if<!std::is_integral<T>::value, nullptr_t>::type = nullptr>
void f(T t)
{
std::cout << "not integer" << std::endl;
return;
}
int main()
{
f(10);
f(5.5);
f("Hello");
return 0;
}
And the warning is:
C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.29.30037\include\ostream(746): warning C4530: C++ exception handler used, but unwind semantics are not enabled. Specify /EHsc
sfinae2.cpp(9): note: see reference to function template instantiation 'std::basic_ostream<char,std::char_traits<char>> &std::operator <<<std::char_traits<char>>(std::basic_ostream<char,std::char_traits<char>> &,const char *)' being compiled
sfinae2.cpp(23): note: see reference to function template instantiation 'void f<int,nullptr>(T)' being compiled
with
[
T=int
]
The warning disappears when compiling with the flag /EHsc
, or when deleting the cout
from both functions.
I want to know why this flag is needed.
Best regards.
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