How to invoke browser to open "about:blank"

Using C code, how to invoke the default browser to open "about:blank" (a blank page)?

I've tried many methods, here are some that don't work:

1. Call <Windows.h>'s ShellExecuteW or ShellExecute passing "open" as its 2nd argument
2. As method 1, but use http:about:blank instead

Results:

1. As "about:blank" contains no "http:" or "https:", so Windows doesn't know to invoke the browser.
2. The browser will open, but results in a default page instead of a blank page

What's more, using something like http:about:blank or http://about:blank may be not correct.

Maybe the only valid url pointing to a blank is about:blank

I've found that AssocQueryString helps (requiring to link against shlwapi.dll),

This is AssocQueryStringW's reference

Here is one possible version of C++ code:

#include<shlwapi.h>

#pragma comment(lib, "Shlwapi.lib")
#pragma comment(lib, "Shell32.lib")

#define F_ASSOC ASSOCF_NONE
#define assoc(buffer, sizep) ::AssocQueryStringW(F_ASSOC, ASSOCSTR_EXECUTABLE,\
   L"http", L"open", (buffer), (sizep))

DWORD getDefaultBrowser(LPWSTR &pszPath){
    DWORD size = 0;
    assoc(NULL, &size); // get required buffer size, returns S_FALSE
    pszPath = new WCHAR[size];
    HRESULT hr = assoc(pszPath,&size); // assert(hr==S_OK);
    return size;
    // remember `delete[]pszPath;`
}

int main(){
    LPWSTR browserPath;
    DWORD len = getDefaultBrowser(browserPath);
    if (len == 0)return -1;

    ShellExecuteW(NULL, L"open", browserPath, L"about:blank", NULL, SW_SHOW);

    delete[] browserPath;
}

Also, corresponding C code:

#include<stdlib.h>
#include<Windows.h>
#include<shlwapi.h>

#pragma comment(lib, "Shlwapi.lib")
#pragma comment(lib, "Shell32.lib")

#define F_ASSOC ASSOCF_NONE
#define assoc(buffer, sizep) AssocQueryStringW(F_ASSOC, ASSOCSTR_EXECUTABLE, \
    L"http", L"open", (buffer), (sizep));
DWORD getDefaultBrowser(LPWSTR* pOut){
    DWORD size = 0;
    assoc(NULL, &size); // get required buffer size, returns S_FALSE
    *pOut = (LPWSTR)malloc(size * sizeof(WCHAR));
    HRESULT hr = assoc(*pOut,&size); // assert(hr==S_OK);
    return size;
    // remember `free(pOut);`
}
int main(){
    //Get default web browser path
    LPWSTR browserPath;
    DWORD len = getDefaultBrowser(&browserPath); 
    if(len == 0) return -1;

    ShellExecuteW(NULL, L"open", browserPath, L"about:blank", NULL, SW_SHOW);

    free(browserPath);
}