| /* CC0 (Public domain) - see LICENSE file for details */ |
| #ifndef CCAN_CHECK_TYPE_H |
| #define CCAN_CHECK_TYPE_H |
| #include "config.h" |
| |
| /** |
| * check_type - issue a warning or build failure if type is not correct. |
| * @expr: the expression whose type we should check (not evaluated). |
| * @type: the exact type we expect the expression to be. |
| * |
| * This macro is usually used within other macros to try to ensure that a macro |
| * argument is of the expected type. No type promotion of the expression is |
| * done: an unsigned int is not the same as an int! |
| * |
| * check_type() always evaluates to 0. |
| * |
| * If your compiler does not support typeof, then the best we can do is fail |
| * to compile if the sizes of the types are unequal (a less complete check). |
| * |
| * Example: |
| * // They should always pass a 64-bit value to _set_some_value! |
| * #define set_some_value(expr) \ |
| * _set_some_value((check_type((expr), uint64_t), (expr))) |
| */ |
| |
| /** |
| * check_types_match - issue a warning or build failure if types are not same. |
| * @expr1: the first expression (not evaluated). |
| * @expr2: the second expression (not evaluated). |
| * |
| * This macro is usually used within other macros to try to ensure that |
| * arguments are of identical types. No type promotion of the expressions is |
| * done: an unsigned int is not the same as an int! |
| * |
| * check_types_match() always evaluates to 0. |
| * |
| * If your compiler does not support typeof, then the best we can do is fail |
| * to compile if the sizes of the types are unequal (a less complete check). |
| * |
| * Example: |
| * // Do subtraction to get to enclosing type, but make sure that |
| * // pointer is of correct type for that member. |
| * #define container_of(mbr_ptr, encl_type, mbr) \ |
| * (check_types_match((mbr_ptr), &((encl_type *)0)->mbr), \ |
| * ((encl_type *) \ |
| * ((char *)(mbr_ptr) - offsetof(enclosing_type, mbr)))) |
| */ |
| #if HAVE_TYPEOF |
| #define check_type(expr, type) \ |
| ((typeof(expr) *)0 != (type *)0) |
| |
| #define check_types_match(expr1, expr2) \ |
| ((typeof(expr1) *)0 != (typeof(expr2) *)0) |
| #else |
| #include <ccan/build_assert/build_assert.h> |
| /* Without typeof, we can only test the sizes. */ |
| #define check_type(expr, type) \ |
| BUILD_ASSERT_OR_ZERO(sizeof(expr) == sizeof(type)) |
| |
| #define check_types_match(expr1, expr2) \ |
| BUILD_ASSERT_OR_ZERO(sizeof(expr1) == sizeof(expr2)) |
| #endif /* HAVE_TYPEOF */ |
| |
| #endif /* CCAN_CHECK_TYPE_H */ |