C++Builder 2007, Union and bit fields

Question

Size of this union return 16 bytes (in C++Builder 2007).

typedef union
{
  struct
  {
    unsigned Type:2; 
    unsigned Prev:31;
    unsigned Next:31;
    unsigned SizeInBytes:32;
  };
} eMyUnion;

How i must modify this union definition, if i want sizeof(eMyUnion) = 12 bytes ?
(I want keep these fields and its sizes, but it can be reordered).
It is possible ?

you probably have to set byte alignment. in vs it's with #pragma pack directive, but in c++ builder i don't know — Hayri Uğur Koltuk, Feb 21 '13 at 11:38

score 1 · Answer 1 · answered Feb 21 '13 at 12:21

1

#pragma pack(push, 1)
  struct
  {
    unsigned Type:2; 
    unsigned Prev:31;
    unsigned Next:31;
    unsigned SizeInBytes:32;
  };
#pragma pack(pop)

answered Feb 21 '13 at 12:21

John Zwinck

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C++Builder 2007, Union and bit fields

1 Answers1