What Breaking Changes Did C 11 Introduce to Existing Code?

Breaking Changes Introduced in C 11

C 11 introduces several breaking changes that may affect the compilation and behavior of existing code.

Core Language Changes:

• Operator Overloading: The introduction of an explicit operator bool() in the standard library has replaced old instances of operator void*(). This change may break code that previously relied on implicit conversions to boolean values.
• Keyword Additions: New keywords, such as alignas, constexpr, and nullptr, can now be used and may conflict with previously valid identifiers.
• Integer Literals: Certain integer literals may change type from unsigned integer to signed long long, leading to potential errors in calculations.
• Division Rounding: Integer division now always rounds towards 0, regardless of the use of floating-point types.
• Implicit Constructor Definitions: Some implicit constructor definitions are now deleted, making previously valid code that calls them invalid.
• Implicit Exception Specifications: User-declared destructors now have an implicit exception specification, which can affect exception handling behavior.
• Dependent Function Calls: Dependent calls of functions with internal linkage are now allowed, altering the resolution of function calls in certain scenarios.

Library Changes:

• Header Conflicts: New standard library headers may conflict with existing headers with similar names, such as and .
• Reserved Namespace: The posix global namespace is now reserved for standardization, raising issues for code that previously defined identifiers in this namespace.
• Macro Conflicts: Macros defined for override, final, carries_dependency, and noreturn are now invalid in C 11, potentially affecting code that uses these macros.

It is important to note that while these changes are significant, many are intentional and aimed at improving the language's soundness and consistency. Programmers should review their codebase тщательно, identify потенциальные breaking changes, and make appropriate modifications to ensure compatibility with C 11.

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