Troubleshooting __int128 Compatibility in Visual Studio

While Visual Studio's syntax highlighting suggests the availability of the __int128 data type, compilation errors reveal that it is not supported on the current architecture. This issue arises when attempting to utilize this 128-bit integer type in C projects within Visual Studio.

Ursache:

According to the Microsoft Developer Network (MSDN), __int128 is not a supported type on the Visual Studio platform. This contradicts the syntax highlighting, which incorrectly suggests its validity.

Lösung:

Despite the syntax highlighting, the compiler accurately detects the lack of __int128 support. Therefore, it is recommended to refrain from using this data type in Visual Studio projects.

Additional Considerations:

• Avoid using __int128 as a type name, as it is likely a reserved word due to the compilation error.
• Recognize that __int128 is not available on x64/IPF architectures through register spanning, unlike __int64 on 32-bit targets.
• The only 128-bit types currently supported in Visual Studio are SIMD types derived from __m128.