TColor Initialise with int works with {} but not ()

Question

I'm using Embarcader C++Builder 10.4.2 with the Clang32 compiler in the IDE to build a VCL Windows 32-bit app.

I used to use () initializers for my own TColor constants when I used the old "Classic" compiler. But the Clang32 compiler doesn't accept this. The Clang32 does accept the same initialize value, but with the C++ 17 (and earlier I think) {} intializers.

Thanks Remy for advice: I should have included error message in my original posting. The error message reported by the Clang32 compiler is:

[C++ Error] Unit1.cpp(15, 13): cannot initialize a variable of type 'const System::Uitypes::TColor' with an rvalue of type 'int'

I don't understand why Clang32 doesn't like the () initializer syntax. Can anyone explain please?

Code example attached:

#include <vcl.h>

const TColor MeterBarBezelRimColour{0x00DDDDDD};   // works with Clang32 - (too "modern" for Classic compiler)
    
const TColor AnotherBezelRimColour(0x00CCCCCC);    // give an error with Clang32 (but does work for Classic compiler).

// WHY is this not accepted by Clang?

Answer 1

Direct initialization doesn't allow an enum to be initialized from int with (..).

And since C++17:

list_initialization allows an enum to be initialized from int with {..}:

Otherwise, if T is a enumeration type that is either scoped or unscoped with fixed underlying type, and if the braced-init-list has only one initializer, and if the conversion from the initializer to the underlying type is non-narrowing, and if the initialization is direct-list-initialization, then the enumeration is initialized with the result of converting the initializer to its underlying type.

Clang is right to accept {..} (since C++17) and reject the (..) construct.

Your "Classic" compiler is wrong in that regard (pre-C++17, it should reject both).