WSL API Test code for Register Distribution. Windows 10 64bit FCU or later only. I tested with mingw-w64 64bit gcc

wslapi_Reg_test.c

#include <stdio.h>
#include <windows.h>

typedef int (WINAPI *FUNC)(PCWSTR,PCWSTR);

int main()
{
    HMODULE hmod;
    FUNC func;
    
    hmodule = LoadLibrary(TEXT("wslapi.dll"));
    if (hmod == NULL) {
        printf("ERROR:wslapi.dll load failed");
        return 1;
    }

        
    func = (FUNC)GetProcAddress(hmod, "WslRegisterDistribution");
    if (func == NULL) {
        FreeLibrary(hmod);
        printf("ERROR:GetProcAddress failed");
        return 1;
    }
    

    int a = func(L"Test",L"install.tar.gz");
    printf("%d",a);

    FreeLibrary(hmod);

    return 0;
}