c++ array copy showing errors in vc++

Question

int a[4] = {10,20,30,40};
std::vector<int> vec(4);
std::copy(a, a + 4, vec.begin());

I'm getting the following errorin vc++, it says warning but flagged as error how shall I solve this ?

Severity Code Description Project File Line Suppression State Error C4996 std::copy::_Unchecked_iterators::_Deprecate: Call to std::copy with parameters that may be unsafe - this call relies on the caller to check that the passed values are correct. To disable this warning, use -D_SCL_SECURE_NO_WARNINGS. See documentation on how to use Visual C++ 'Checked Iterators' ConsoleApplication3 e:\programs\vc\include\xutility 2372

Answer 1

By default, MSVC deprecate certain APIs it deems unsafe. Basically, raw memory access where a mistake in a single parameter could lead to buffer overruns on the reading or writing side.

Among them is std::copy.

Calling a deprecated API leads to MSVC generating an error message.

You can disable this deprecation with -D_SCL_SECURE_NO_WARNINGS as the error suggests.

This may solve your problem; it involves wrapping the raw pointer with a "checked array iterator", which means that (at least in debug) you get assertions and/or exceptions instead of memory corruption if you get it wrong.

Buffer overruns are one of the more pervasive errors in C/C++ applications; treat them as a serious problem, even if it has runtime cost, unless and until you prove that a given path is performance critical. At that point, find a way to statically prove your array sizes are correct.