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。
archcharshortintlongptrlong-longu8u16u32u64
i686 124448124 8
i38612 4 4 4 8 1 2 4 8
alpha12 4 8 8 8 1 2 4 8
armv411 2 4 4 4 8 1 2 4 8
ia641 2 4 8 8 8 1 2 4 8
m68k1 2 4 4 4 8 1 2 4 8
mips 1 2 4 4 4 8 1 2 4 8
ppc 1 2 4 4 4 8 1 2 4 8
sparc 1 2 4 4 4 8 1 2 4 8
sparc64 1 2 4 4 4 8 1 2 4 8
.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 s32;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_HIGHMEM64Gtypedef u64 dma_addr_t;#elsetypedef u32 dma_addr_t;#endiftypedef u64 dma64_addr_t;#ifdef CONFIG_LBDtypedef u64 sector_t;#define HAVE_SECTOR_T#endiftypedef 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_NAMEStypedef __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*/#elsetypedef __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_Ttypedef __kernel_size_t size_t;#endif#ifndef _SSIZE_T#define _SSIZE_Ttypedef __kernel_ssize_t ssize_t;#endif#ifndef _PTRDIFF_T#define _PTRDIFF_Ttypedef __kernel_ptrdiff_t ptrdiff_t;#endif#ifndef _TIME_T#define _TIME_Ttypedef __kernel_time_t time_t;#endif#ifndef _CLOCK_T#define _CLOCK_Ttypedef __kernel_clock_t clock_t;#endif#ifndef _CADDR_T#define _CADDR_Ttypedef __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_Ttypedef 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#endiftypedef __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 */
后来逐渐有广州花城的，
