Is Unsigned size_t Still Relevant in Modern C/C Development?

The Rationale for the Unsigned Nature of size_t

Bjarne Stroustrup's caution against using unsigned integers to represent positive values has sparked a debate over the practicality of size_t as an unsigned datatype.

Historically, size_t was conceived on 16-bit architectures where limiting strings to 32 KB would be unreasonable. To address this, the C standard mandated ptrdiff_t (the signed counterpart of size_t) to effectively operate within 17 bits, a requirement that may still hold relevance in embedded systems.

However, for modern 32-bit and 64-bit platforms, the rationale for unsigned size_t becomes questionable due to C/C 's unfortunate implicit conversion rules. Unsigned types become a source of errors when used for numeric operations, as negative values are interpreted as large positive ones.

This has led to experts like Scott Meyers recommending the avoidance of unsigned integers in interfaces, regardless of the expected value range. Simply employing typedef int MyType can eliminate this issue without impairing code readability.

In summary, the choice of unsigned size_t was made in the context of early architectural constraints. While it may have been appropriate at the time, it is arguably less practical in modern programming environments where implicit conversion rules present a significant risk of errors.

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