Linux2.6内核 -- 结构的初始化
Linux 内核中用到了大量的结构体,在编码规范中也给出了结构体初始化的规则,这篇文章中有对其的解释:http://blog.csdn.net/dlutbrucezhang/article/details/10296897,不过,这篇文章中并没有给出实例分析,下面我写了一段测试程序:
#include<stdio.h> #include<string.h> struct test { int test_value1; float test_value2; char *test_value3; }; int main(void) { int i; char my_name[] = "DLUTBruceZhang"; char my_school[] = "DLUT"; for(i = 0; i < 2; i++){ if (i % 2 == 0){ struct test my_test = { .test_value1 = 10, .test_value2 = 10.0, .test_value3 = my_name, }; printf("test_value1 = %d, test_value2 = %f,\ test_value3 = %s\n", my_test.test_value1, my_test.test_value2, my_test.test_value3); } else { struct test my_test = { .test_value1 = 100, .test_value2 = 100.0, .test_value3 = my_school, }; printf("test_value1 = %d, test_value2 = %f,\ test_value3 = %s\n", my_test.test_value1, my_test.test_value2, my_test.test_value3); } } struct test my_test = { /*.test_value1 = 10,*/ /*.test_value2 = 10.0,*/ /*.test_value3 = my_name,*/ }; printf("test_value1 = %d, test_value2 = %f,\ test_value3 = %s\n", my_test.test_value1, my_test.test_value2, my_test.test_value3); return 0; }
分析:
1.首先给出结构体的定义,它包含三个字段,一个整型,一个浮点型,一个字符指针
struct test {
int test_value1;
float test_value2;
char *test_value3;
};
2.两次赋初值,根据情况不同,对其进行赋值,赋值方法采用的是 Linux 内核编码规范中的方法(这里忽略了标识符)
struct test my_test = {
.test_value1 = 10,
.test_value2 = 10.0,
.test_value3 = my_name,
};
struct test my_test = {
.test_value1 = 100,
.test_value2 = 100.0,
.test_value3 = my_school,
};
3.不赋初值的情况是整型默认为 0,浮点型默认为 0.0,字符指针默认为 NULL
struct test my_test = {
/*.test_value1 = 10,*/
/*.test_value2 = 10.0,*/
/*.test_value3 = my_name,*/
};
下面,运行这个测试程序,验证上述说法: