step into standard wstdio functions in Visual Studio 2019 - c

Question

I want to find the reason why with the new feature setlocale(LC_ALL, ".utf8") the standard function fgetwc() can't read '\u2013' (EN DASH) from a utf8 text file and instead returns WEOF. Maybe find a workaround.
I disabled "Only my code" and enabled symbol downloading for C:\WINDOWS\SysWOW64\ucrtbased.dll that contains fgetwc
However, when I try to step into that function it cannot find fgetwc.cpp.
These two locations don't contain that file and I can't find any other place:
C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\crt\src\
C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.28.29333\crt\src\
This is my test program:
#include <stdio.h>
#include <locale.h>
#include <wchar.h>
#include <stdlib.h>
int main()
{
wint_t wc; // = L'\u2013';
FILE* file;
printf("%s\n", setlocale(LC_ALL, ".utf8"));
file = fopen("test.txt", "r");
wc = fgetwc(file);
// ffff '?' 0 0
fprintf(stdout, "%04x '%lc' %d %d\n", wc, wc, ferror(file), feof(file));
return 0;
}
It prints ffff instead of 2013. ferror() and feof() return false.
test.txt:
–
It's encoded as E2 80 93

Answer 1

For reading the UTF-8 file, optionally drop the setlocale call, and replace the fopen line with:
file = fopen("test.txt", "r, ccs=utf-8");
The fopen documentation states:
ccs=encoding -- Specifies the encoded character set to use (one of UTF-8, UTF-16LE, or UNICODE) for this file. Leave unspecified if you want ANSI encoding.
This appears to imply that the ccs=UTF-8 encoding must be specified explicitly in order to read a file as UTF-8 text.
Though, on the other hand, "ANSI" used to mean either the active codepage, or the system default locale. With the recent support in Windows 10 1903 and later for UTF-8 as an active codepage, it would be expected that "ANSI encoding" be the same as "UTF-8 encoding" when the current locale is UTF-8. However, that does not seem to be the case with the current implementation of the UCRT.
For writing the wide char, #include <io.h> and <fcntl.h>, and replace the fprintf line with:
_setmode(_fileno(stdout), _O_U16TEXT);
wprintf(L"%04x '%wc' %d %d\n", wc, wc, ferror(file), feof(file));
The printf documentation states:
wprintf is a wide-character version of printf; format is a wide-character string. wprintf and printf behave identically if the stream is opened in ANSI mode. printf does not currently support output into a UNICODE stream.