C语言数据类型所占空间大小

/*
* datasize.c -- print the size of common data items
* This runs with any Linux kernel (not any Unix, because of <linux/types.h>)
*
* Copyright (C) 2001 Alessandro Rubini and Jonathan Corbet
* Copyright (C) 2001 O'Reilly & Associates
*
* The source code in this file can be freely used, adapted,
* and redistributed in source or binary form, so long as an
* acknowledgment appears in derived source files.  The citation
* should list that the code comes from the book "Linux Device
* Drivers" by Alessandro Rubini and Jonathan Corbet, published
* by O'Reilly & Associates.   No warranty is attached;
* we cannot take responsibility for errors or fitness for use.
*/
#include <stdio.h>
#include <sys/utsname.h>
#include <linux/types.h>

int main(int argc, char **argv)
{
struct utsname name;

uname(&name); /* never fails :) */
printf("arch   Size:  char  short  int  long   ptr long-long "
" u8 u16 u32 u64\n");
printf(       "%-12s  %3i   %3i   %3i   %3i   %3i   %3i      "
"%3i %3i %3i %3i\n",
name.machine,
(int)sizeof(char), (int)sizeof(short), (int)sizeof(int),
(int)sizeof(long),
(int)sizeof(void *), (int)sizeof(long long), (int)sizeof(__u8),
(int)sizeof(__u16), (int)sizeof(__u32), (int)sizeof(__u64));
return 0;
}