c++ - 如何查看在运行时将哪个函数分配给函数指针..？

Question

#include<stdio.h>

int add(int i,int j)
{
        printf("\n%s\n",__FUNCTION__);

        return (i*j);
}

int (*fp)(int,int);

void main()
{
        int j=2;
        int i=5;

        printf("\n%s\n",__FUNCTION__);

        fp=add;

        printf("\n%d\n",(*fp)(2,5));
        printf("\n%s\n",*fp);
}

Answer 1

You can compare the function pointer with a pointer to function. Like this :

    if (fp==add)
        printf("\nadd\n");

There are no other (standard) ways¹.

This

printf("\n%s\n",*fp);

is a compilation error.

---

There are platform specific ways. For linux, this works :

#include<stdio.h>
#include <execinfo.h>

int add(int i,int j)

{

        printf("\n%s\n",__FUNCTION__);

        return (i*j);

}

int (*fp)(int,int);

union
{
    int (*fp)(int,int);
    void* fp1;
} fpt;

int main()
{
        fp=add;


        fpt.fp=fp;

        char ** funName = backtrace_symbols(&fpt.fp1, 1);
        printf("%s\n",*funName);
}