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function point

Jarvee wang
Offline

flowing is error,Please help me!!

#include <stdio.h>
#define NUMBER 2


int max(int a[])
{
int z;
if(a[0]>a[1]) z=a[0]; else z=a[1];
return(z);
}



int process(void (* fun)(void *p),void *arg)
{
int z;
z=(int *)(* fun)((int *)arg);
return(z);
}



main()
{
int a[NUMBER];
int i;
int d;
for(i=0;i++;i<NUMBER) a[i]=i;

d=process(max,a);
while(1);
}

Parents
  • 0 Offline

    Your code is based on an invalid assumption, and it contains various bugs.

    Generally speaking, it's almost always an error to cast a function pointer to any other function pointer type.

    On top of that, the casts you do apply are wrong, here:

    int z;
z=(int *)(* fun)((int *)arg);

    The cast to (int *) is seriously wrong. You have to cast "fun" back to the real signature before you're allowed to use it for calling max(), which will fix the return type in the same step:

    
typedef int (*my_fp_type)(int *);

int z;
z=((my_fp_type)fun)((int *)arg);

Reply
  • 0 Offline

    Your code is based on an invalid assumption, and it contains various bugs.

    Generally speaking, it's almost always an error to cast a function pointer to any other function pointer type.

    On top of that, the casts you do apply are wrong, here:

    int z;
z=(int *)(* fun)((int *)arg);

    The cast to (int *) is seriously wrong. You have to cast "fun" back to the real signature before you're allowed to use it for calling max(), which will fix the return type in the same step:

    
typedef int (*my_fp_type)(int *);

int z;
z=((my_fp_type)fun)((int *)arg);

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