src/include/lwip/arch.h - third_party/lwip - Git at Google

 /**
  * @file
  * Support for different processor and compiler architectures
  */

 /*
  * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without modification,
  * are permitted provided that the following conditions are met:
  *
  * 1. Redistributions of source code must retain the above copyright notice,
  *    this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright notice,
  *    this list of conditions and the following disclaimer in the documentation
  *    and/or other materials provided with the distribution.
  * 3. The name of the author may not be used to endorse or promote products
  *    derived from this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
  * OF SUCH DAMAGE.
  *
  * This file is part of the lwIP TCP/IP stack.
  *
  * Author: Adam Dunkels <adam@sics.se>
  *
  */
 #ifndef LWIP_HDR_ARCH_H
 #define LWIP_HDR_ARCH_H

 #ifndef LITTLE_ENDIAN
 #define LITTLE_ENDIAN 1234
 #endif

 #ifndef BIG_ENDIAN
 #define BIG_ENDIAN 4321
 #endif

 #include "arch/cc.h"

 /**
  * @defgroup compiler_abstraction Compiler/platform abstraction
  * @ingroup sys_layer
  * All defines related to this section must not be placed in lwipopts.h,
  * but in arch/cc.h!
  * These options cannot be \#defined in lwipopts.h since they are not options
  * of lwIP itself, but options of the lwIP port to your system.
  * @{
  */

 /** Define the byte order of the system.
  * Needed for conversion of network data to host byte order.
  * Allowed values: LITTLE_ENDIAN and BIG_ENDIAN
  */
 #ifndef BYTE_ORDER
 #define BYTE_ORDER LITTLE_ENDIAN
 #endif

 /** Define random number generator function of your system */
 #ifndef LWIP_RAND
 #define LWIP_RAND() ((u32_t)rand())
 #endif

 /** Platform specific diagnostic output.\n
  * Note the default implementation pulls in printf, which may
  * in turn pull in a lot of standard libary code. In resource-constrained
  * systems, this should be defined to something less resource-consuming.
  */
 #ifndef LWIP_PLATFORM_DIAG
 #define LWIP_PLATFORM_DIAG(x)	do {printf x;} while(0)
 #include <stdio.h>
 #include <stdlib.h>
 #endif

 /** Platform specific assertion handling.\n
  * Note the default implementation pulls in printf, fflush and abort, which may
  * in turn pull in a lot of standard libary code. In resource-constrained
  * systems, this should be defined to something less resource-consuming.
  */
 #ifndef LWIP_PLATFORM_ASSERT
 #define LWIP_PLATFORM_ASSERT(x) do {printf("Assertion \"%s\" failed at line %d in %s\n", \
                                      x, __LINE__, __FILE__); fflush(NULL); abort();} while(0)
 #include <stdio.h>
 #include <stdlib.h>
 #endif

 /** Define this to 1 in arch/cc.h of your port if you do not want to
  * include stddef.h header to get size_t. You need to typedef size_t
  * by yourself in this case.
  */
 #ifndef LWIP_NO_STDDEF_H
 #define LWIP_NO_STDDEF_H 0
 #endif

 #if !LWIP_NO_STDDEF_H
 #include <stddef.h> /* for size_t */
 #endif

 /** Define this to 1 in arch/cc.h of your port if your compiler does not provide
  * the stdint.h header. You need to typedef the generic types listed in
  * lwip/arch.h yourself in this case (u8_t, u16_t...).
  */
 #ifndef LWIP_NO_STDINT_H
 #define LWIP_NO_STDINT_H 0
 #endif

 /* Define generic types used in lwIP */
 #if !LWIP_NO_STDINT_H
 #include <stdint.h>
 typedef uint8_t   u8_t;
 typedef int8_t    s8_t;
 typedef uint16_t  u16_t;
 typedef int16_t   s16_t;
 typedef uint32_t  u32_t;
 typedef int32_t   s32_t;
 typedef uintptr_t mem_ptr_t;
 #endif

 /** Define this to 1 in arch/cc.h of your port if your compiler does not provide
  * the inttypes.h header. You need to define the format strings listed in
  * lwip/arch.h yourself in this case (X8_F, U16_F...).
  */
 #ifndef LWIP_NO_INTTYPES_H
 #define LWIP_NO_INTTYPES_H 0
 #endif

 /* Define (sn)printf formatters for these lwIP types */
 #if !LWIP_NO_INTTYPES_H
 #include <inttypes.h>
 #ifndef X8_F
 #define X8_F  "02" PRIx8
 #endif
 #ifndef U16_F
 #define U16_F PRIu16
 #endif
 #ifndef S16_F
 #define S16_F PRId16
 #endif
 #ifndef X16_F
 #define X16_F PRIx16
 #endif
 #ifndef U32_F
 #define U32_F PRIu32
 #endif
 #ifndef S32_F
 #define S32_F PRId32
 #endif
 #ifndef X32_F
 #define X32_F PRIx32
 #endif
 #ifndef SZT_F
 #define SZT_F PRIuPTR
 #endif
 #endif

 /** C++ const_cast<target_type>(val) equivalent to remove constness from a value (GCC -Wcast-qual) */
 #ifndef LWIP_CONST_CAST
 #define LWIP_CONST_CAST(target_type, val) ((target_type)((ptrdiff_t)val))
 #endif

 /** Get rid of alignment cast warnings (GCC -Wcast-align) */
 #ifndef LWIP_ALIGNMENT_CAST
 #define LWIP_ALIGNMENT_CAST(target_type, val) LWIP_CONST_CAST(target_type, val)
 #endif

 /** Get rid of warnings related to pointer-to-numeric and vice-versa casts,
  * e.g. "conversion from 'u8_t' to 'void *' of greater size"
  */
 #ifndef LWIP_PTR_NUMERIC_CAST
 #define LWIP_PTR_NUMERIC_CAST(target_type, val) LWIP_CONST_CAST(target_type, val)
 #endif

 /** Allocates a memory buffer of specified size that is of sufficient size to align
  * its start address using LWIP_MEM_ALIGN.
  * You can declare your own version here e.g. to enforce alignment without adding
  * trailing padding bytes (see LWIP_MEM_ALIGN_BUFFER) or your own section placement
  * requirements.\n
  * e.g. if you use gcc and need 32 bit alignment:\n
  * \#define LWIP_DECLARE_MEMORY_ALIGNED(variable_name, size) u8_t variable_name[size] \_\_attribute\_\_((aligned(4)))\n
  * or more portable:\n
  * \#define LWIP_DECLARE_MEMORY_ALIGNED(variable_name, size) u32_t variable_name[(size + sizeof(u32_t) - 1) / sizeof(u32_t)]
  */
 #ifndef LWIP_DECLARE_MEMORY_ALIGNED
 #define LWIP_DECLARE_MEMORY_ALIGNED(variable_name, size) u8_t variable_name[LWIP_MEM_ALIGN_BUFFER(size)]
 #endif

 /** Calculate memory size for an aligned buffer - returns the next highest
  * multiple of MEM_ALIGNMENT (e.g. LWIP_MEM_ALIGN_SIZE(3) and
  * LWIP_MEM_ALIGN_SIZE(4) will both yield 4 for MEM_ALIGNMENT == 4).
  */
 #ifndef LWIP_MEM_ALIGN_SIZE
 #define LWIP_MEM_ALIGN_SIZE(size) (((size) + MEM_ALIGNMENT - 1U) & ~(MEM_ALIGNMENT-1U))
 #endif

 /** Calculate safe memory size for an aligned buffer when using an unaligned
  * type as storage. This includes a safety-margin on (MEM_ALIGNMENT - 1) at the
  * start (e.g. if buffer is u8_t[] and actual data will be u32_t*)
  */
 #ifndef LWIP_MEM_ALIGN_BUFFER
 #define LWIP_MEM_ALIGN_BUFFER(size) (((size) + MEM_ALIGNMENT - 1U))
 #endif

 /** Align a memory pointer to the alignment defined by MEM_ALIGNMENT
  * so that ADDR % MEM_ALIGNMENT == 0
  */
 #ifndef LWIP_MEM_ALIGN
 #define LWIP_MEM_ALIGN(addr) ((void *)(((mem_ptr_t)(addr) + MEM_ALIGNMENT - 1) & ~(mem_ptr_t)(MEM_ALIGNMENT-1)))
 #endif

 #ifdef __cplusplus
 extern "C" {
 #endif

 /** Packed structs support.
   * Placed BEFORE declaration of a packed struct.\n
   * For examples of packed struct declarations, see include/lwip/prot/ subfolder.\n
   * A port to GCC/clang is included in lwIP, if you use these compilers there is nothing to do here.
   */
 #ifndef PACK_STRUCT_BEGIN
 #define PACK_STRUCT_BEGIN
 #endif /* PACK_STRUCT_BEGIN */

 /** Packed structs support.
   * Placed AFTER declaration of a packed struct.\n
   * For examples of packed struct declarations, see include/lwip/prot/ subfolder.\n
   * A port to GCC/clang is included in lwIP, if you use these compilers there is nothing to do here.
   */
 #ifndef PACK_STRUCT_END
 #define PACK_STRUCT_END
 #endif /* PACK_STRUCT_END */

 /** Packed structs support.
   * Placed between end of declaration of a packed struct and trailing semicolon.\n
   * For examples of packed struct declarations, see include/lwip/prot/ subfolder.\n
   * A port to GCC/clang is included in lwIP, if you use these compilers there is nothing to do here.
   */
 #ifndef PACK_STRUCT_STRUCT
 #if defined(__GNUC__) || defined(__clang__)
 #define PACK_STRUCT_STRUCT __attribute__((packed))
 #else
 #define PACK_STRUCT_STRUCT
 #endif
 #endif /* PACK_STRUCT_STRUCT */

 /** Packed structs support.
   * Wraps u32_t and u16_t members.\n
   * For examples of packed struct declarations, see include/lwip/prot/ subfolder.\n
   * A port to GCC/clang is included in lwIP, if you use these compilers there is nothing to do here.
   */
 #ifndef PACK_STRUCT_FIELD
 #define PACK_STRUCT_FIELD(x) x
 #endif /* PACK_STRUCT_FIELD */

 /** Packed structs support.
   * Wraps u8_t members, where some compilers warn that packing is not necessary.\n
   * For examples of packed struct declarations, see include/lwip/prot/ subfolder.\n
   * A port to GCC/clang is included in lwIP, if you use these compilers there is nothing to do here.
   */
 #ifndef PACK_STRUCT_FLD_8
 #define PACK_STRUCT_FLD_8(x) PACK_STRUCT_FIELD(x)
 #endif /* PACK_STRUCT_FLD_8 */

 /** Packed structs support.
   * Wraps members that are packed structs themselves, where some compilers warn that packing is not necessary.\n
   * For examples of packed struct declarations, see include/lwip/prot/ subfolder.\n
   * A port to GCC/clang is included in lwIP, if you use these compilers there is nothing to do here.
   */
 #ifndef PACK_STRUCT_FLD_S
 #define PACK_STRUCT_FLD_S(x) PACK_STRUCT_FIELD(x)
 #endif /* PACK_STRUCT_FLD_S */

 /** Packed structs support using \#include files before and after struct to be packed.\n
  * The file included BEFORE the struct is "arch/bpstruct.h".\n
  * The file included AFTER the struct is "arch/epstruct.h".\n
  * This can be used to implement struct packing on MS Visual C compilers, see
  * the Win32 port in the lwIP contrib repository for reference.
  * For examples of packed struct declarations, see include/lwip/prot/ subfolder.\n
  * A port to GCC/clang is included in lwIP, if you use these compilers there is nothing to do here.
  */
 #ifdef __DOXYGEN__
 #define PACK_STRUCT_USE_INCLUDES
 #endif

 /** Eliminates compiler warning about unused arguments (GCC -Wextra -Wunused). */
 #ifndef LWIP_UNUSED_ARG
 #define LWIP_UNUSED_ARG(x) (void)x
 #endif /* LWIP_UNUSED_ARG */

 /**
  * @}
  */

 #ifdef __cplusplus
 }
 #endif

 #endif /* LWIP_HDR_ARCH_H */
	/**
	* @file
	* Support for different processor and compiler architectures
	*/

	/*
	* Copyright (c) 2001-2004 Swedish Institute of Computer Science.
	* All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without modification,
	* are permitted provided that the following conditions are met:
	*
	* 1. Redistributions of source code must retain the above copyright notice,
	* this list of conditions and the following disclaimer.
	* 2. Redistributions in binary form must reproduce the above copyright notice,
	* this list of conditions and the following disclaimer in the documentation
	* and/or other materials provided with the distribution.
	* 3. The name of the author may not be used to endorse or promote products
	* derived from this software without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
	* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
	* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
	* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
	* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
	* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
	* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
	* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
	* OF SUCH DAMAGE.
	*
	* This file is part of the lwIP TCP/IP stack.
	*
	* Author: Adam Dunkels <adam@sics.se>
	*
	*/
	#ifndef LWIP_HDR_ARCH_H
	#define LWIP_HDR_ARCH_H

	#ifndef LITTLE_ENDIAN
	#define LITTLE_ENDIAN 1234
	#endif

	#ifndef BIG_ENDIAN
	#define BIG_ENDIAN 4321
	#endif

	#include "arch/cc.h"

	/**
	* @defgroup compiler_abstraction Compiler/platform abstraction
	* @ingroup sys_layer
	* All defines related to this section must not be placed in lwipopts.h,
	* but in arch/cc.h!
	* These options cannot be \#defined in lwipopts.h since they are not options
	* of lwIP itself, but options of the lwIP port to your system.
	* @{
	*/

	/** Define the byte order of the system.
	* Needed for conversion of network data to host byte order.
	* Allowed values: LITTLE_ENDIAN and BIG_ENDIAN
	*/
	#ifndef BYTE_ORDER
	#define BYTE_ORDER LITTLE_ENDIAN
	#endif

	/** Define random number generator function of your system */
	#ifndef LWIP_RAND
	#define LWIP_RAND() ((u32_t)rand())
	#endif

	/** Platform specific diagnostic output.\n
	* Note the default implementation pulls in printf, which may
	* in turn pull in a lot of standard libary code. In resource-constrained
	* systems, this should be defined to something less resource-consuming.
	*/
	#ifndef LWIP_PLATFORM_DIAG
	#define LWIP_PLATFORM_DIAG(x) do {printf x;} while(0)
	#include <stdio.h>
	#include <stdlib.h>
	#endif

	/** Platform specific assertion handling.\n
	* Note the default implementation pulls in printf, fflush and abort, which may
	* in turn pull in a lot of standard libary code. In resource-constrained
	* systems, this should be defined to something less resource-consuming.
	*/
	#ifndef LWIP_PLATFORM_ASSERT
	#define LWIP_PLATFORM_ASSERT(x) do {printf("Assertion \"%s\" failed at line %d in %s\n", \
	x, __LINE__, __FILE__); fflush(NULL); abort();} while(0)
	#include <stdio.h>
	#include <stdlib.h>
	#endif

	/** Define this to 1 in arch/cc.h of your port if you do not want to
	* include stddef.h header to get size_t. You need to typedef size_t
	* by yourself in this case.
	*/
	#ifndef LWIP_NO_STDDEF_H
	#define LWIP_NO_STDDEF_H 0
	#endif

	#if !LWIP_NO_STDDEF_H
	#include <stddef.h> /* for size_t */
	#endif

	/** Define this to 1 in arch/cc.h of your port if your compiler does not provide
	* the stdint.h header. You need to typedef the generic types listed in
	* lwip/arch.h yourself in this case (u8_t, u16_t...).
	*/
	#ifndef LWIP_NO_STDINT_H
	#define LWIP_NO_STDINT_H 0
	#endif

	/* Define generic types used in lwIP */
	#if !LWIP_NO_STDINT_H
	#include <stdint.h>
	typedef uint8_t u8_t;
	typedef int8_t s8_t;
	typedef uint16_t u16_t;
	typedef int16_t s16_t;
	typedef uint32_t u32_t;
	typedef int32_t s32_t;
	typedef uintptr_t mem_ptr_t;
	#endif

	/** Define this to 1 in arch/cc.h of your port if your compiler does not provide
	* the inttypes.h header. You need to define the format strings listed in
	* lwip/arch.h yourself in this case (X8_F, U16_F...).
	*/
	#ifndef LWIP_NO_INTTYPES_H
	#define LWIP_NO_INTTYPES_H 0
	#endif

	/* Define (sn)printf formatters for these lwIP types */
	#if !LWIP_NO_INTTYPES_H
	#include <inttypes.h>
	#ifndef X8_F
	#define X8_F "02" PRIx8
	#endif
	#ifndef U16_F
	#define U16_F PRIu16
	#endif
	#ifndef S16_F
	#define S16_F PRId16
	#endif
	#ifndef X16_F
	#define X16_F PRIx16
	#endif
	#ifndef U32_F
	#define U32_F PRIu32
	#endif
	#ifndef S32_F
	#define S32_F PRId32
	#endif
	#ifndef X32_F
	#define X32_F PRIx32
	#endif
	#ifndef SZT_F
	#define SZT_F PRIuPTR
	#endif
	#endif

	/** C++ const_cast<target_type>(val) equivalent to remove constness from a value (GCC -Wcast-qual) */
	#ifndef LWIP_CONST_CAST
	#define LWIP_CONST_CAST(target_type, val) ((target_type)((ptrdiff_t)val))
	#endif

	/** Get rid of alignment cast warnings (GCC -Wcast-align) */
	#ifndef LWIP_ALIGNMENT_CAST
	#define LWIP_ALIGNMENT_CAST(target_type, val) LWIP_CONST_CAST(target_type, val)
	#endif

	/** Get rid of warnings related to pointer-to-numeric and vice-versa casts,
	* e.g. "conversion from 'u8_t' to 'void *' of greater size"
	*/
	#ifndef LWIP_PTR_NUMERIC_CAST
	#define LWIP_PTR_NUMERIC_CAST(target_type, val) LWIP_CONST_CAST(target_type, val)
	#endif

	/** Allocates a memory buffer of specified size that is of sufficient size to align
	* its start address using LWIP_MEM_ALIGN.
	* You can declare your own version here e.g. to enforce alignment without adding
	* trailing padding bytes (see LWIP_MEM_ALIGN_BUFFER) or your own section placement
	* requirements.\n
	* e.g. if you use gcc and need 32 bit alignment:\n
	* \#define LWIP_DECLARE_MEMORY_ALIGNED(variable_name, size) u8_t variable_name[size] \_\_attribute\_\_((aligned(4)))\n
	* or more portable:\n
	* \#define LWIP_DECLARE_MEMORY_ALIGNED(variable_name, size) u32_t variable_name[(size + sizeof(u32_t) - 1) / sizeof(u32_t)]
	*/
	#ifndef LWIP_DECLARE_MEMORY_ALIGNED
	#define LWIP_DECLARE_MEMORY_ALIGNED(variable_name, size) u8_t variable_name[LWIP_MEM_ALIGN_BUFFER(size)]
	#endif

	/** Calculate memory size for an aligned buffer - returns the next highest
	* multiple of MEM_ALIGNMENT (e.g. LWIP_MEM_ALIGN_SIZE(3) and
	* LWIP_MEM_ALIGN_SIZE(4) will both yield 4 for MEM_ALIGNMENT == 4).
	*/
	#ifndef LWIP_MEM_ALIGN_SIZE
	#define LWIP_MEM_ALIGN_SIZE(size) (((size) + MEM_ALIGNMENT - 1U) & ~(MEM_ALIGNMENT-1U))
	#endif

	/** Calculate safe memory size for an aligned buffer when using an unaligned
	* type as storage. This includes a safety-margin on (MEM_ALIGNMENT - 1) at the
	* start (e.g. if buffer is u8_t[] and actual data will be u32_t*)
	*/
	#ifndef LWIP_MEM_ALIGN_BUFFER
	#define LWIP_MEM_ALIGN_BUFFER(size) (((size) + MEM_ALIGNMENT - 1U))
	#endif

	/** Align a memory pointer to the alignment defined by MEM_ALIGNMENT
	* so that ADDR % MEM_ALIGNMENT == 0
	*/
	#ifndef LWIP_MEM_ALIGN
	#define LWIP_MEM_ALIGN(addr) ((void *)(((mem_ptr_t)(addr) + MEM_ALIGNMENT - 1) & ~(mem_ptr_t)(MEM_ALIGNMENT-1)))
	#endif

	#ifdef __cplusplus
	extern "C" {
	#endif

	/** Packed structs support.
	* Placed BEFORE declaration of a packed struct.\n
	* For examples of packed struct declarations, see include/lwip/prot/ subfolder.\n
	* A port to GCC/clang is included in lwIP, if you use these compilers there is nothing to do here.
	*/
	#ifndef PACK_STRUCT_BEGIN
	#define PACK_STRUCT_BEGIN
	#endif /* PACK_STRUCT_BEGIN */

	/** Packed structs support.
	* Placed AFTER declaration of a packed struct.\n
	* For examples of packed struct declarations, see include/lwip/prot/ subfolder.\n
	* A port to GCC/clang is included in lwIP, if you use these compilers there is nothing to do here.
	*/
	#ifndef PACK_STRUCT_END
	#define PACK_STRUCT_END
	#endif /* PACK_STRUCT_END */

	/** Packed structs support.
	* Placed between end of declaration of a packed struct and trailing semicolon.\n
	* For examples of packed struct declarations, see include/lwip/prot/ subfolder.\n
	* A port to GCC/clang is included in lwIP, if you use these compilers there is nothing to do here.
	*/
	#ifndef PACK_STRUCT_STRUCT
	#if defined(__GNUC__) \|\| defined(__clang__)
	#define PACK_STRUCT_STRUCT __attribute__((packed))
	#else
	#define PACK_STRUCT_STRUCT
	#endif
	#endif /* PACK_STRUCT_STRUCT */

	/** Packed structs support.
	* Wraps u32_t and u16_t members.\n
	* For examples of packed struct declarations, see include/lwip/prot/ subfolder.\n
	* A port to GCC/clang is included in lwIP, if you use these compilers there is nothing to do here.
	*/
	#ifndef PACK_STRUCT_FIELD
	#define PACK_STRUCT_FIELD(x) x
	#endif /* PACK_STRUCT_FIELD */

	/** Packed structs support.
	* Wraps u8_t members, where some compilers warn that packing is not necessary.\n
	* For examples of packed struct declarations, see include/lwip/prot/ subfolder.\n
	* A port to GCC/clang is included in lwIP, if you use these compilers there is nothing to do here.
	*/
	#ifndef PACK_STRUCT_FLD_8
	#define PACK_STRUCT_FLD_8(x) PACK_STRUCT_FIELD(x)
	#endif /* PACK_STRUCT_FLD_8 */

	/** Packed structs support.
	* Wraps members that are packed structs themselves, where some compilers warn that packing is not necessary.\n
	* For examples of packed struct declarations, see include/lwip/prot/ subfolder.\n
	* A port to GCC/clang is included in lwIP, if you use these compilers there is nothing to do here.
	*/
	#ifndef PACK_STRUCT_FLD_S
	#define PACK_STRUCT_FLD_S(x) PACK_STRUCT_FIELD(x)
	#endif /* PACK_STRUCT_FLD_S */

	/** Packed structs support using \#include files before and after struct to be packed.\n
	* The file included BEFORE the struct is "arch/bpstruct.h".\n
	* The file included AFTER the struct is "arch/epstruct.h".\n
	* This can be used to implement struct packing on MS Visual C compilers, see
	* the Win32 port in the lwIP contrib repository for reference.
	* For examples of packed struct declarations, see include/lwip/prot/ subfolder.\n
	* A port to GCC/clang is included in lwIP, if you use these compilers there is nothing to do here.
	*/
	#ifdef __DOXYGEN__
	#define PACK_STRUCT_USE_INCLUDES
	#endif

	/** Eliminates compiler warning about unused arguments (GCC -Wextra -Wunused). */
	#ifndef LWIP_UNUSED_ARG
	#define LWIP_UNUSED_ARG(x) (void)x
	#endif /* LWIP_UNUSED_ARG */

	/**
	* @}
	*/

	#ifdef __cplusplus
	}
	#endif

	#endif /* LWIP_HDR_ARCH_H */