What's the C++ version of Guid.NewGuid()?

Question

I need to create a GUID in an unmanaged windows C++ project. I\'m used to C#, where I\'d use Guid.NewGuid(). What\'s the (unmanaged windows) C++ vers

Answer 1

To generate a new guid in windows and get the resulting value as a string.

#include 
#include 
#include 
#include 
#include 

int main()
{
    GUID guid;
    CoCreateGuid(&guid);

    std::ostringstream os;
    os << std::hex << std::setw(8) << std::setfill('0') << guid.Data1;
    os << '-';
    os << std::hex << std::setw(4) << std::setfill('0') << guid.Data2;
    os << '-';
    os << std::hex << std::setw(4) << std::setfill('0') << guid.Data3;
    os << '-';
    os << std::hex << std::setw(2) << std::setfill('0') << static_cast(guid.Data4[0]);
    os << std::hex << std::setw(2) << std::setfill('0') << static_cast(guid.Data4[1]);
    os << '-';
    os << std::hex << std::setw(2) << std::setfill('0') << static_cast(guid.Data4[2]);
    os << std::hex << std::setw(2) << std::setfill('0') << static_cast(guid.Data4[3]);
    os << std::hex << std::setw(2) << std::setfill('0') << static_cast(guid.Data4[4]);
    os << std::hex << std::setw(2) << std::setfill('0') << static_cast(guid.Data4[5]);
    os << std::hex << std::setw(2) << std::setfill('0') << static_cast(guid.Data4[6]);
    os << std::hex << std::setw(2) << std::setfill('0') << static_cast(guid.Data4[7]);

    std::string s(os.str());
    std::cout << s << std::endl;
}

Alternatively, you could use sprintf_s for the string conversion

GUID guid;
CoCreateGuid(&guid);
char guidStr[37];
sprintf_s(
    guidStr,
    "%08lX-%04hX-%04hX-%02hhX%02hhX-%02hhX%02hhX%02hhX%02hhX%02hhX%02hhX",
    guid.Data1, guid.Data2, guid.Data3,
    guid.Data4[0], guid.Data4[1], guid.Data4[2], guid.Data4[3],
    guid.Data4[4], guid.Data4[5], guid.Data4[6], guid.Data4[7]);
std::string s(guidStr);