libkmod/macro.h

/*
 * libkmod - interface to kernel module operations
 *
 * Copyright (C) 2011  ProFUSION embedded systems
 * Copyright (C) 2011  Lucas De Marchi <lucas.de.marchi@gmail.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation version 2.1.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#ifndef _LIBKMOD_MACRO_H_
#define _LIBKMOD_MACRO_H_

#include <stddef.h>

#define BUILD_ASSERT(cond) \
	do { (void) sizeof(char [1 - 2*!(cond)]); } while(0)

#define EXPR_BUILD_ASSERT(cond) \
	(sizeof(char [1 - 2*!(cond)]) - 1)

#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
/* Without typeof, we can only test the sizes. */
#define check_type(expr, type)					\
	EXPR_BUILD_ASSERT(sizeof(expr) == sizeof(type))

#define check_types_match(expr1, expr2)				\
	EXPR_BUILD_ASSERT(sizeof(expr1) == sizeof(expr2))
#endif /* HAVE_TYPEOF */

#define container_of(member_ptr, containing_type, member)		\
	((containing_type *)						\
	 ((char *)(member_ptr) - offsetof(containing_type, member))	\
	 - check_types_match(*(member_ptr), ((containing_type *)0)->member))

/* Attributes */

#define __must_check __attribute__((warn_unused_result))
#define __printf_format(a,b) __attribute__((format (printf, a, b)))
#if !defined(__always_inline)
#define __always_inline __inline__ __attribute__((always_inline))
#endif

#endif