FUNC1 p = &inc; 变异为什么通不过

#include <stdio.h>int inc( int a ){return ( ++a);}int multi( int *a, int *b, int *c ){return ( *c = *a * *b );}typedef int(FUNC1) (int in);typedef int(FUNC2)  (int*, int*,int *);void show( FUNC2 fun, int arg1, int *arg2 ){FUNC1 p = &inc;//int temp = inc( arg1 );int temp = p( arg1 );fun( &temp, &arg1,arg2 );printf( "%d\n", *arg2 );}main(){inta ;show( multi, 10, &a );return 0;}