Mercurial > dovecot > core-2.2
changeset 22931:31856a233751
lib: introduce container_of
This is a simple but type safe implementation.
| author | Josef 'Jeff' Sipek <jeff.sipek@dovecot.fi> |
|---|---|
| date | Tue, 13 Sep 2016 15:01:56 -0400 |
| parents | bfeda12bb54a |
| children | ffa75273f796 |
| files | src/lib/macros.h |
| diffstat | 1 files changed, 4 insertions(+), 0 deletions(-) [+] |
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--- a/src/lib/macros.h Sun Apr 29 12:31:23 2018 +0300 +++ b/src/lib/macros.h Tue Sep 13 15:01:56 2016 -0400 @@ -26,6 +26,10 @@ #define CONST_PTR_OFFSET(ptr, offset) \ ((const void *) (((const unsigned char *) (ptr)) + (offset))) +#define container_of(ptr, type, name) \ + (type *)((uintptr_t)(ptr) - (uintptr_t)offsetof(type, name) + \ + COMPILE_ERROR_IF_TYPES_NOT_COMPATIBLE(ptr, &((type *) 0)->name)) + /* Don't use simply MIN/MAX, as they're often defined elsewhere in include files that are included after this file generating tons of warnings. */ #define I_MIN(a, b) (((a) < (b)) ? (a) : (b))