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Some compilers support various struct layouts:
- the fastest one
- the smallest one
- the MS one
- the ABI specified one

For ex. CodeWarrior let the user choose that using a pragma,
the syntax look likes:

#pragma push alignment
#pragma align 68k
struct T_68K { int i; char c; };
#pragma align powerpc
struct T_PPC { int i; char c; };
#pragma pop alignment

T_68K has the preferred alignement for the 68000, etc

One could even imagine non conforming layouts,
where &x.c < &x.i...

What is the recommended way to manage that:

- pragmas:
  - until C9X, aren't manageable via #ifdef
  - aren't scoped: one needs push/pop commands
    to save previous behaviour

- extern "language-convention" { declarations }
  - C++ only
  - intended to name a language (like C, FORTRAN),
    not a precise ABI ("
  - intended to apply to functions and
    functions pointers only

- any others ?

--

Valentin Bonnard


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