Bug 23067 – importC: offsetof macro assumes size_t is defined

the __builtin_offsetof macro in druntime uses size_t to cast the result type, but size_t isn't a built-in type in C so it only works after the type has been defined struct S { int x; }; //int y = __builtin_offsetof(struct S, x); int y = ((size_t)((char *)&((struct S *)0)->x - (char *)0)); test.c(3): Error: undefined identifier `size_t` when the typeof() PR is merged, this can be fixed by using "typeof(sizeof(0))" to get the size_t type in the macro

@WalterBright created dlang/druntime pull request #3819 "fix Issue 23067 - importC: offsetof macro assumes size_t is defined" fixing this issue: - fix Issue 23067 - importC: offsetof macro assumes size_t is defined https://github.com/dlang/druntime/pull/3819

dlang/druntime pull request #3819 "fix Issue 23067 - importC: offsetof macro assumes size_t is defined" was merged into master: - 469d67061474837b46fbd3a0037db7170d174ca6 by Walter Bright: fix Issue 23067 - importC: offsetof macro assumes size_t is defined https://github.com/dlang/druntime/pull/3819

It works now if you #include "importc.h". This will become automatic soon.