C语言问题析之 inline 与 一般函数（八）

    声明为内联函数，就会在宏一样，每次调用时都将就地展开，没有函数调用的开销

    展开为内联函数意味着在调用函数的地方放置函数代码。由于没有进行函数调用，因此没有将返回地址和参数压入栈的开销

#include <stdio.h>
#include <time.h>

float add_time(long int a, float b)
{
    float result;
    result = a + b;
    return result;
}

inline float add_time_inline(long int a, float b)
{
    float result;
    result = a + b;
    return result;
}

int main()
{
    long int i;
    float result = 0;

    time_t start_time, stop_time;
    printf("add_time working...\n");
    time(&start_time);
    for(i = 0;i <= 1000000000; i++)
    {
        result = add_time(i, result);
    }
    time(&stop_time);
    printf("using time:%ld\n",stop_time - start_time);

    printf("add_time_incline working...\n");
    result = 0;
    time(&start_time);
    for(i = 0; i <= 1000000000; i++)
    {
        result = add_time_inline(i, result);
    }
    time(&stop_time);
    printf("using time:%ld\n",stop_time - start_time);

    return 0;

}

ywx@yuweixian:~/yu/c$ ./te
add_time working...
using time:16
add_time_incline working...
using time:14
ywx@yuweixian: