C language variable parameter "..."

A variable parameter function represents: type fun (int num, ...)

Wherein the type represents the type of function return value, NUM represents the number of parameters, and "..." indicates all parameters.

Example: char fun (int num, ...);

Two, va_list, va_start (), va_arg (), va_end () function and the original meaning of representation.

　　1, va_list: represents the parameter list.

　　2, va_start (): a list of initialization parameters.

　　3, va_arg (): Get a different type parameters.

　　4, va_end (): Empty the list of parameters.

　　5、typedef char * va_list; 

　　　  #define _INTSIZEOF(n) ((sizeof(n)+sizeof(int)-1)&~(sizeof(int) - 1) )
　　　  #define va_start(ap,v) ( ap = (va_list)&v + _INTSIZEOF(v) )
　　　  #define va_arg(ap,t) ( *(t *)((ap += _INTSIZEOF(t)) - _INTSIZEOF(t)) )
　　 　 #define va_end(ap) ( ap = (va_list)0 )

　　6, (a + b-1) & ~ (b-1): When a and b are both n-th power of 2, can be obtained the smallest multiple of the maximum of a and b.

　　　　Therefore, (sizeof (n) + sizeof ( int) -1) & ~ (sizeof (int) - 1) may be used for byte alignment.

#include <stdio.h>  
#include <stdarg.h> int FUNC ( int NUM, ...)   // NUM representative of the number of parameters {  
     char ** ARR; 
     int Inter [ 2 ];
     Double Dou [ . 3 ];
     int I; 
    the va_list list;   // parameter list 
    the va_start (list, NUM);   // initialization parameter list for (I = 0 ; I < 2 ; I ++ ) { 
        Inter [I] = the va_arg (list, int );   // Get int type parameter 
        printf ( "



    inter[%d]=%d\n",i,inter[i]);
    }
    
    for(i=0;i<3;i++){
        dou[i]=va_arg(list,double);  // 获取double类型参数 [Warning] 'float' is promoted to 'double' when passed through '...'
        printf("dou[%d]=%lf\n",i,dou[i]);
    }
    
    for(i=0;i<5;i++){
        arr[i]=va_arg(list,char*);  // 获取int类型参数
        printf("arr[%d]=%s\n",i,arr[i]);
    }
    return 0;
}
 
int main(){
    func(10,1,2,1.0,2.0,3.0,"aaa","bbb","ccc","ddd","eee");
}