Compiler Warning (level 1) C4566
character represented by universal-character-name 'char' cannot be represented in the current code page (page)
Not every Unicode character can be represented in your current ANSI code page.
Narrow strings (one-byte characters) are converted to multi-byte characters whereas wide strings (two-byte characters) are not.
The following sample generates C4566:
// C4566.cpp
// compile with: /W1
int main() {
char c1 = '\u03a0'; // C4566
char c2 = '\u0642'; // C4566
wchar_t c3 = L'\u03a0'; // OK
wchar_t c4 = L'\u0642'; // OK
}