Question

I am sorry if this is a really simple question but I am really rusty in C and googling hasn’t helped so far. I have a C function that takes in an array of structs and an integer:

int foo(struct record *records, int n)
{

}

and also a linked list where each node has a struct:

struct rnode
{
    struct record rec;
    struct rnode *next;
}

and struct record is:

struct record
{
    enum recordtype type;
    union recordvalue
    {
        int intval;
        char strval[19];
    } value;
};

inside foo(struct record , int) I am iterating through the linked list and assigning the first “n” struct records into the array like:

int foo(struct record *records, int n)
{
    int count = 0;
    struct rnode *cur = recordlist;
    while(cur != NULL)
    {
        records[count] = cur->rec; //Basically, how do I write this line?
        printf("%d\n", records[count].type); //Both these print the correct values
        printf("%d\n", records[count].value.intval); //Prints correct values
        count++;
    }
}

I tried doing:
records[count] = cur->rec

which compiles but when I do the following:

struct record *records = malloc(sizeof(struct record)*n);
foo(records, n); //This should populate the array records but it isn't.
//If I print record[0].value.intval here I get 0.

but when I pass &records[0] to another function like:

checkrecord(&record[0]);

where checkrecord is declared:

checkrecord(const struct record *r)

inside that function, r->type and r->value.intval both return 0 instead of the correct value.

I’m pretty sure I’m storing the struct record into the array correctly, but I’m not sure what else I’m doing wrong.

I don’t mean to sound stubborn but the issue is that the checkrecord() function I am not at liberty to change but I can change how I pass the parameters to it.

Answer 1

Thanks for your help everyone. It was actually a memory issue elsewhere. The above code is correct.