Return structure with flexible array member

Question

I need to return a structure with a flexible array member from a C function but can\'t figure out why it doesn\'t compile. I know that returning arrays can be achieved by en

Answer 1

Few things:

1) change the struct defenation to:

 struct data_array {
    long length;
    double* data;
          ^
};

2) This is how you should use malloc to allocate memory for your array:

a.data =  malloc (length * sizeof(double));

EDIT

There are too many mistakes, just follow this code:

#include 
#include 
struct data_array {
    long length;
    double* data;
};
struct data_array* test (int length) {
    struct data_array* a;
    a = malloc (sizeof (data_array));
    a->data = malloc (length*sizeof(double));
    a->length = length;
    return a;
}

int main () {
    data_array* x;
    x = test (5);
    for (int i=0; i<5; i++) {
        x->data[i] = i+0.5;
    }
    for (int i=0; i<5; i++) {
        printf ("%f\n" , x->data[i]);
    }
}

NOTE that you might need to add casting to the types when useing maloc (my visual force me to do so, otherwise it's compile error. But it simply worng).