| Message ID | 20210414074128.31268-2-mforney@mforney.org |
|---|---|
| State | Accepted |
| Headers | show |
| Series | [1/2] libext2fs: use statement-expression for container_of only on GNU-compatible compilers | expand |
On Wed, Apr 14, 2021 at 12:41:28AM -0700, Michael Forney wrote: > offsetof is a standard C feature available from stddef.h, going > back all the way to ANSI C. > > Signed-off-by: Michael Forney <mforney@mforney.org> Thanks, applied. > Perhaps there is some reason to prefer compiler builtins over libc > that I'm not seeing? It's because I pulled container_of from the kernel, and the kernel header files has to provide offsetof since we don't use the standard header files --- and it has to work across a bunch of compilers and architectures. - Ted
diff --git a/lib/ext2fs/compiler.h b/lib/ext2fs/compiler.h index 03c35ab8..42faa61c 100644 --- a/lib/ext2fs/compiler.h +++ b/lib/ext2fs/compiler.h @@ -1,18 +1,7 @@ #ifndef _EXT2FS_COMPILER_H #define _EXT2FS_COMPILER_H -#ifndef __has_builtin -#define __has_builtin(x) 0 -#endif - -#undef offsetof -#if __has_builtin(__builtin_offsetof) -#define offsetof(TYPE, MEMBER) __builtin_offsetof(TYPE, MEMBER) -#elif defined(__compiler_offsetof) -#define offsetof(TYPE,MEMBER) __compiler_offsetof(TYPE,MEMBER) -#else -#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER) -#endif +#include <stddef.h> #ifdef __GNUC__ #define container_of(ptr, type, member) ({ \
offsetof is a standard C feature available from stddef.h, going back all the way to ANSI C. Signed-off-by: Michael Forney <mforney@mforney.org> --- Perhaps there is some reason to prefer compiler builtins over libc that I'm not seeing? lib/ext2fs/compiler.h | 13 +------------ 1 file changed, 1 insertion(+), 12 deletions(-)