I want to make a function pointer array and be able to call them in a for-loop. How can I achieve this? I have tried:
void (**a) (int);
a[0] = &my_func1;
a[1] = &my_func2;
a[2] = &my_func3;
for ( i = 0; i < 3; i++){
a[0]();
(*a[0])(); // Neither does work
}
But I am missing some syntax I guess:
error: too few arguments to function ‘*(a + (long unsigned int)((long unsigned int)i * 8ul))’
The function you declare is expected to take an int as a parameter:
a[0](1);
Also note that you declare a pointer to pointer for the functions, but you don't allocate any memory for them (I assume this is only in the example) Otherwise it should probably be:
void (*a[3]) (int);
You are declaring that a is a pointer to a pointer to (or an array of pointers to) a function that takes an int as a parameter - so you need to pass an int when you call the functions, e.g. a[0](42);.
I guess the below code is what you need.
typedef void * func_pointer(int);
func_pointer fparr[10];
for(int i = 0; i<10; i++)
{
fparr[i](arg); //pass the integer argument here
}
typedef statement, I encounter an error when compile the code, and typedef void (*func_pointer)(int); works. Pls double check:).1) Where have you allocated or defined array to store function addresses?
2) in loop you are always calling (*a[0])();,There should be loop counter
You forgot to give an argument to your function.
void (**a) (int); // here it takes an int argument
a[0] = &my_func1;
a[1] = &my_func2;
a[2] = &my_func3;
for ( i = 0; i < 3; i++){
a[0](); // here you do not give an argument
}
But be careful, you do not allocate memory to your a array, and it fails with a nice segmentation fault error.
void my_func1(int i) {
;
}
void my_func2(int i) {
;
}
void my_func3(int i) {
;
}
int main() {
void (**a) (int);
a = malloc(3*sizeof(void*)); // allocate array !
a[0] = &my_func1;
a[1] = &my_func2;
a[2] = &my_func3;
for (int i = 0; i < 3; i++){
a[i](1); // respect your own function signature
}
free(a); // it's always a good habit to free the memory you take
return 0;
}
You can typedef void (*pfun)(int); and then pfun a[3]; is the array you want.
The following code may work for you:
typedef void (*pfun)(int);
int main() {
pfun a[3];
a[0] = myfunc1; // or &myfunc1 whatever you like
a[1] = myfunc2;
a[2] = myfunc3;
}
You can define your function-array with the needed size and initialize it with your functions like:
void my_func1(int x){}
void my_func2(int x){}
void my_func3(int x){}
void (*a[])(int)={my_func1,my_func2,my_func3};
int i;
for(i=0;i<sizeof a/sizeof*a;++i)
a[i](i);
The address-operator '&' before any function-name is redundant.
