Why Are Anonymous Structs Absent in C While Anonymous Unions Exist?

Anonymous Structs in C : Exploring the Rationale Behind Their Exclusion

Despite support for anonymous unions in standard C , anonymous structs remain absent. This inquiry delves into the rationale behind this disparity, addressing questions of technical limitations, philosophical considerations, or practical insufficiency.

The absence of anonymous structs in C stems from their omission in C, the language from which C evolved. For compatibility reasons, C adopted anonymous unions, but structs were excluded. This decision was based on the lack of a compelling need for anonymous structs in C 's context.

One key reason is that anonymous structs provide limited functionality. The ability to access union members interchangeably with struct members (.v[i] or .x, .y, .z) is not well-defined in C , potentially leading to undefined behavior.

C provides alternative solutions for creating user-defined types. A vector3 struct with float elements can be implemented as follows:

struct vector3 {
  float v[3];
  float &operator[] (int i) { return v[i]; }
  float &x() { return v[0]; }
  float &y() { return v[1]; }
  float &z() { return v[2]; }
};

This approach avoids the ambiguity associated with anonymous structs and offers greater flexibility in accessing and modifying members.

In summary, the exclusion of anonymous structs in C is not due to technical roadblocks or philosophical objections. Rather, it reflects a calculated decision based on the lack of a compelling need and the availability of alternative, well-defined solutions for creating user-defined types.

The above is the detailed content of Why Are Anonymous Structs Absent in C While Anonymous Unions Exist?. For more information, please follow other related articles on the PHP Chinese website!