diff options
Diffstat (limited to 'gcc/ginclude')
| -rw-r--r-- | gcc/ginclude/stddef.h | 21 |
1 files changed, 6 insertions, 15 deletions
diff --git a/gcc/ginclude/stddef.h b/gcc/ginclude/stddef.h index d19d78a3140..1bb3e90bc9b 100644 --- a/gcc/ginclude/stddef.h +++ b/gcc/ginclude/stddef.h @@ -413,21 +413,12 @@ typedef __WINT_TYPE__ wint_t; #ifndef __cplusplus #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER) #else -/* In C++ a POD type can have a user defined address-of operator, and - that will break offsetof. C++ core defect 273 addresses this and - claims that reinterpret_casts to char & type are sufficient to - overcome this problem. - - (reinterpret_cast <size_t> - (&reinterpret_cast <char &>(static_cast <TYPE *> (0)->MEMBER))) - - But, such casts are not permitted in integral constant expressions, - which offsetof is supposed to be. - - It appears that offsetof is unimplementable in C++ without a - compiler extension. */ -#define offsetof(TYPE, MEMBER) (reinterpret_cast <size_t> \ - (&static_cast<TYPE *> (0)->MEMBER)) +/* The cast to "char &" below avoids problems with user-defined + "operator &", which can appear in a POD type. */ +#define offsetof(TYPE, MEMBER) \ + (__offsetof__ (reinterpret_cast <size_t> \ + (&reinterpret_cast <char &> \ + (static_cast<TYPE *> (0)->MEMBER)))) #endif /* C++ */ #endif /* _STDDEF_H was defined this time */ |