`std::wstring` argument order

[Ericson2314]

I now see

../src/libutil/windows/environment-variables.cc:17:24: warning: narrowing conversion of ‘bufferSize’ from ‘DWORD’ {aka ‘long unsigned int’} to ‘wchar_t’ [-Wnarrowing]
   17 |     std::wstring value{bufferSize, L'\0'};

in Windows builds, but in 355f08a we explicitly flipped it to fix a Clang MinGW warning.

Does the right argument order depend on the C++ standard library implementation? What is going on!

CC @puffnfresh

[xokdvium]

Oh hell, that's because it's calling the initializer list ctor from 2 elements and doing the implicit conversion from std::size_t to wchar_t:)

Here's an example on compiler explorer:

https://godbolt.org/z/jMa9GP5sq

[xokdvium]

You need to need use regular braces -- not the curly ones (a.k.a. unicorn initialization):

The following has very different meanings:

std::wstring(bufferSize, L'\0') // has size = bufferSize
std::wstring{bufferSize, L'\0'} // has size = 2