内核代码中一些c语言用法

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container_of，（C 语言 up cast） 

内核中的定义：

Cscope tag: container_of
   #   line  filename / context / line
   1     27  drivers/gpu/drm/radeon/mkregtable.c >
             #define container_of(ptr, type, member) ({ \
   2     63  drivers/staging/lustre/include/linux/libcfs/libcfs.h >
             #define container_of(ptr, type, member) \
   3     78  drivers/staging/rtl8192e/rtllib.h >
             #define container_of(ptr, type, member) ({ \
   4     61  drivers/staging/rtl8192u/ieee80211/ieee80211.h >
             #define container_of(ptr, type, member) ({ \
   5    791  include/linux/kernel.h >
             #define container_of(ptr, type, member) ({ \
   6     18  scripts/kconfig/list.h >
             #define container_of(ptr, type, member) ({ \
   7     26  tools/perf/util/include/linux/kernel.h >
             #define container_of(ptr, type, member) ({ \
   8     84  tools/virtio/linux/kernel.h >
             #define container_of(ptr, type, member) ({ \

scripts/kconfig/list.h

 1 #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
 2 
 3 /**
 4  * container_of - cast a member of a structure out to the containing structure
 5  * @ptr:        the pointer to the member.
 6  * @type:       the type of the container struct this is embedded in.
 7  * @member:     the name of the member within the struct.
 8  *
 9  */
10 #define container_of(ptr, type, member) ({                      11         const typeof( ((type *)0)->member ) *__mptr = (ptr);    12         (type *)( (char *)__mptr - offsetof(type,member) );})

分析详见：

http://www.cnblogs.com/cute/archive/2011/04/01/2002474.html

结构体和数据 

cat test.c

 1 #include  2 
 3 #define MAXTITL 30
 4 #define MAXAUTL 20
 5 
 6 struct book {
 7   float off;
 8   char title[MAXTITL];
 9   char author[MAXAUTL];
10   float value;
11 
12 };
13 
14 int main()
15 {
16     puts("C lange test!");
17     struct book b1 = { .value =  19.9, .author = "author", .title="C test tutorial" };
18     printf("Book value: %f\n", b1.value);
19     printf("Book author: %s\n", b1.author);
20     printf("Book title: %s\n", b1.title);
21     printf("Book off: %f\n", b1.off);
22     int m,n;
23     int a2[10] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 0};
24     for(n=0;n11;n++)
25         printf("%d\n",a2[n]);
26     int a1[10] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 0, };
27     for(m=0;m11;m++)
28         printf("%d\n",a1[m]);
29     return 0;
30 }

gcc test.c -o test
./test

内核代码中一些c语言用法

标签：compiler   执行   virt   ptr   翻译   comm   drive   语言   csdn   

原文地址：https://www.cnblogs.com/shaohef/p/3930380.html