ID Number: Q70142
5.00 5.10 6.00 6.00a 6.00ax 7.00 | 5.10 6.00 6.00a
MS-DOS | OS/2
Summary:
The sample code below illustrates how to use function pointers to call
functions that take different parameters than those with which the
pointer was declared. The function is cast to the type of the function
pointer during the first assignment, then the function pointer is cast
to the type of the function to be called. Using typedefs generally
makes it easier than casting the pointer directly.
Sample Code
-----------
/* Compile options needed: none
*/
#include <stdio.h>
typedef int (*footype) (char *, char *);
typedef void (*gootype) (void);
typedef int (* fptype) (void);
int func1(char *, char *);
void func2(void);
void main(void)
{
fptype ptr;
ptr = (fptype) func1;
((footype) ptr)("one", "two");
ptr = (fptype) func2;
((gootype) ptr)();
}
int func1(char *a, char *b)
{
return printf("func1 took two parameters: %s and %s\n", a, b);
}
void func2(void)
{
printf("func2 did not take any parameters\n");
}
Additional reference words: 6.00 6.00a 6.00ax 7.00 argument list