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当Linux内核在体系结构差异较大的平台之间移植时，会产生与数据类型相关的问题。

.在编译内核时使用 -Wall  -W strict-prototypes 选项, 可以避免很多错误的发生

.内核使用的基本数据类型主要有:

int           标准C语言整数类型

u32         32位整数类型

pid_t       特定内核对象pid的类型

.在不同的CPU体系结构上，C语言的数据类型所占空间不一样。

.内核中的地址是unsigned long类型， 指针大小和long类型相同

.内核提供下列数据类型， 所有类型在头文件<asm/types.h>中声明， 这个文件又被头文件<Linux/types.h>所包含， 下面是 include/asm/typs.h文件

[File] /usr/src/kernels/2.6.9-22.EL-i686/include/asm-i386/types.h






#ifndef _I386_TYPES_H

#define _I386_TYPES_H

#ifndef __ASSEMBLY__

typedef unsigned short umode_t;

/*

* __xx is ok: it doesn’t pollute the POSIX namespace. Use these in the

* header files exported to user space

*/

typedef __signed__ char

__s8

;

typedef unsigned char

__u8

;

typedef __signed__ short

__s16

;

typedef unsigned short

__u16

;

typedef __signed__ int

__s32

;

typedef unsigned int

__u32

;

#if defined(__GNUC__) && !defined(__STRICT_ANSI__)

typedef __signed__ long long

__s64

;

typedef unsigned long long

__u64

;

#endif

#endif /* __ASSEMBLY__ */

/*

* These aren’t exported outside the kernel to avoid name space clashes

*/

#ifdef __KERNEL__

#define BITS_PER_LONG 32

#ifndef __ASSEMBLY__

#include <linux/config.h>

typedef signed char

s8

;

typedef unsigned char

u8

;

typedef signed short

s16

;

typedef unsigned short

u16

;

typedef signed int

s3

2;

typedef unsigned int

u32

;

typedef signed long long

s64

;

typedef unsigned long long

u64

;

/* DMA addresses come in generic and 64-bit flavours.  */

#ifdef CONFIG_HIGHMEM64G

typedef u64

dma_addr_t

;

#else

typedef u32

dma_addr_t

;

#endif

typedef u64

dma64_addr_t

;

#ifdef CONFIG_LBD

typedef u64

sector_t

;

#define HAVE_SECTOR_T

#endif

typedef unsigned short

kmem_bufctl_t

;

#endif /* __ASSEMBLY__ */

#endif /* __KERNEL__ */

#endif

[File] /usr/src/kernels/2.6.9-22.EL-i686/include/linux/types.h

#ifndef _LINUX_TYPES_H

#define _LINUX_TYPES_H

#ifdef    __KERNEL__

#include <linux/config.h>

#define BITS_TO_LONGS(bits) /

(((bits)+BITS_PER_LONG-1)/BITS_PER_LONG)

#define DECLARE_BITMAP(name,bits) /

unsigned long name[BITS_TO_LONGS(bits)]

#endif

#include <linux/posix_types.h>

#include <asm/types.h>

#ifndef __KERNEL_STRICT_NAMES

typedef __u32

__kernel_dev_t;

typedef __kernel_fd_set

fd_set

;

typedef __kernel_dev_t

dev_t

;

typedef __kernel_ino_t

ino_t

;

typedef __kernel_mode_t

mode_t

;

typedef __kernel_nlink_t

nlink_t

;

typedef __kernel_off_t

off_t

;

typedef __kernel_pid_t

pid_t

;

typedef __kernel_daddr_t

daddr_t

;

typedef __kernel_key_t

key_t

;

typedef __kernel_suseconds_t

suseconds_t

;

typedef __kernel_timer_t

timer_t

;

typedef __kernel_clockid_t

clockid_t

;

typedef __kernel_mqd_t

mqd_t

;

#ifdef __KERNEL__

typedef __kernel_uid32_t

uid_t

;

typedef __kernel_gid32_t

gid_t

;

typedef __kernel_uid16_t

uid16_t

;

typedef __kernel_gid16_t

gid16_t

;

#ifdef CONFIG_UID16

/* This is defined by include/asm-{arch}/posix_types.h */

typedef __kernel_old_uid_t

old_uid_t

;

typedef __kernel_old_gid_t

old_gid_t

;

#endif /* CONFIG_UID16 */

/* libc5 includes this file to define uid_t, thus uid_t can never change

* when it is included by non-kernel code

*/

#else

typedef __kernel_uid_t

uid_t

;

typedef __kernel_gid_t

gid_t

;

#endif /* __KERNEL__ */

#if defined(__GNUC__) && !defined(__STRICT_ANSI__)

typedef __kernel_loff_t        loff_t;

#endif

/*

* The following typedefs are also protected by individual ifdefs for

* historical reasons:

*/

#ifndef _SIZE_T

#define _SIZE_T

typedef __kernel_size_t

size_t

;

#endif

#ifndef _SSIZE_T

#define _SSIZE_T

typedef __kernel_ssize_t

ssize_t

;

#endif

#ifndef _PTRDIFF_T

#define _PTRDIFF_T

typedef __kernel_ptrdiff_t

ptrdiff_t

;

#endif

#ifndef _TIME_T

#define _TIME_T

typedef __kernel_time_t

time_t

;

#endif

#ifndef _CLOCK_T

#define _CLOCK_T

typedef __kernel_clock_t

clock_t

;

#endif

#ifndef _CADDR_T

#define _CADDR_T

typedef __kernel_caddr_t

caddr_t

;

#endif

/* bsd */

typedef unsigned char

u_char

;

typedef unsigned short

u_short

;

typedef unsigned int

u_int

;

typedef unsigned long

u_long

;

/* sysv */

typedef unsigned char

unchar

;

typedef unsigned short

ushort

;

typedef unsigned int

uint

;

typedef unsigned long

ulong

;

#ifndef __BIT_TYPES_DEFINED__

#define __BIT_TYPES_DEFINED__

typedef        __u8

u_int8_t

;

typedef        __s8

int8_t

;

typedef        __u16

u_int16_t

;

typedef        __s16

int16_t

;

typedef        __u32

u_int32_t

;

typedef        __s32

int32_t

;

#endif /* !(__BIT_TYPES_DEFINED__) */

typedef        __u8

uint8_t

;

typedef        __u16

uint16_t

;

typedef        __u32

uint32_t

;

#if defined(__GNUC__) && !defined(__STRICT_ANSI__)

typedef        __u64

uint64_t

;

typedef        __u64

u_int64_t

;

typedef        __s64

int64_t

;

#endif

/*

* The type used for indexing onto a disc or disc partition.

* If required, asm/types.h can override it and define

* HAVE_SECTOR_T

*/

#ifndef HAVE_SECTOR_T

typedef unsigned long

sector_t

;

#endif

/*

* The type of an index into the pagecache.  Use a #define so asm/types.h

* can override it.

*/

#ifndef pgoff_t

#define

pgoff_t

unsigned long

#endif

#ifdef __CHECKER__

#define __bitwise __attribute__((bitwise))

#else

#define __bitwise

#endif

typedef __u16

__bitwise __le16

;

typedef __u16

__bitwise __be16

;

typedef __u32

__bitwise __le32

;

typedef __u32

__bitwise __be32

;

typedef __u64

__bitwise __le64

;

typedef __u64

__bitwise __be64

;

#endif /* __KERNEL_STRICT_NAMES */

/*

* Below are truly Linux-specific types that should never collide with

* any application/library that wants linux/types.h.

*/

struct

ustat

{

__kernel_daddr_t

f_tfree

;

__kernel_ino_t

f_tinode

;

char

f_fname[6]

;

char

f_fpack[6]

;

};

#endif /* _LINUX_TYPES_H */