Summary

Fixes #4966 - Resolves compilation error when using Poco::format with C++23 and std::format.

Problem

When compiling with C++23 and including both Poco/Format.h and the standard <format> header (either directly or transitively), the compiler encounters ambiguity between Poco::format and std::format functions.

This issue is particularly evident when:

• Using C++23 standard
• Using libstdc++ 14 or later
• Including Poco headers in consumer projects (not when building Poco itself)
• Using C++20 modules with Poco headers in the global module fragment

The ambiguity occurs in the formatAny() helper functions which call format() without explicit namespace qualification, allowing ADL (Argument-Dependent Lookup) to consider both Poco::format and std::format as candidates.

Solution

Use explicit global namespace qualification (::Poco::format) in the formatAny() helper functions to ensure only Poco::format is considered, eliminating the ambiguity with std::format.

Changes

• Modified Foundation/include/Poco/Format.h:
  • Changed Poco::format() to ::Poco::format() in both formatAny() inline functions

Testing

• Verified Foundation library builds successfully
• Tested compilation with C++23 including both <format> and Poco/Format.h
• The fix ensures backward compatibility while resolving the C++23 ambiguity