kernel探索之linux/typecheck.h

#ifndef TYPECHECK_H_INCLUDED
#define TYPECHECK_H_INCLUDED

/*
 * Check at compile time that something is of a particular type.
 * Always evaluates to 1 so you may use it easily in comparisons.
 */
#define typecheck(type,x) \
({ type __dummy; \
 typeof(x) __dummy2; \
 (void)(&__dummy == &__dummy2); \
 1; \
})

/*
 * Check at compile time that 'function' is a certain type, or is a pointer
 * to that type (needs to use typedef for the function type.)
 */
#define typecheck_fn(type,function) \
({ typeof(type) __tmp = function; \
 (void)__tmp; \
})

#endif  /* TYPECHECK_H_INCLUDED */

typecheck(type, x)用於檢查x是不是"type"的資料型態，如果不是，compiler會出現warning: comparison of distinct pointer types lacks a cast提醒programmer。

typecheck_fn(type, function)用於檢查"function"是不是和"type"有相同的資料型態，如果不是，compiler會出現warning: initialization from incompatible pointer type提醒programmer。