Came across this: #ifdef __GNUC__ #define PACKED __attribute__((packed)) #else #define PACKED #endif
typedef enum { // Lots o' stuff } PACKED my_enum_t; typedef struct { // Lots o' stuff const void *ptr; } PACKED my_struct_t; There are a handful of interesting (read: annoying ;) ) problems that are (*ahem*) packed into that: 1. Totally different ABI based on whether or not the **C** side was compiled with a GNU compiler. 2. How to do conditional "align(1)" with minimal ugliness. 3. WTF does it even mean to have a packed enum? 4. Having a pointer at the end of a packed struct is asking for trouble according to D's docs ("The garbage collector assumes that pointers and references to gc allocated objects will be on size_t byte boundaries. If they are not, undefined behavior will result.") Probably nothing that can be done about this one, though, other than just expect the user to be careful. 5. From what I can gather from GCC and DMD docs, it sounds like __attribute__((packed)) means: align(1) struct my_struct_t{ align(1): // blah, blah, members } BUT, are there any other...ummm..."fun" surprises that could pop up and need to be taken into account? 6. The easy one: I'm pretty sure "const void *ptr" translates to "const(void)* ptr", right? For the moment, my "solution" is to just include a note saying "Don't compile the *.c files with __GNUC__ defined" ;) But what would be the best realistic way to handle these issues? Any established practices?