CODEWITHSUNDEEP
cstruct
progNewbie
progNewbie

Reputation: 4822

How to read array out of struct?

I have this C code:

struct ATAInfo* data;

data = (struct ATAInfo*)malloc(512);

Then I call a function, which fills the struct. This is a bit difficult to explain, because i call a function, making a syscall through an interrupt, which reads information form my cd-rom device. I call it this way:

ata_identify(0, data)

And the Function is defined like this:

bool ataIdentify(int device, struct ATAInfo *ataInfo){

Now i fill it with this:

uint16_t pointer = ataInfo;
uint16_t word;
for (int i = 0; i < 256; i++)
{
    word = inw(DATA_PORT);
    *(uint16_t *) pointer = word;
    pointer ++;
}

Now I want to read one attribute out of the struct, which is declared like this:

uint8_t ModelNumber[40];

I did this:

printf("name: %s\n", data->ModelNumber);

But I get "name: (null)".

Upvotes: 0

Views: 99

Answers (1)

R Sahu
R Sahu

Reputation: 206607

This block of code does not seem right:

uint16_t pointer = ataInfo;
uint16_t word;
for (int i = 0; i < 256; i++)
{
    word = inw(DATA_PORT);
    *(uint16_t *) pointer = word;
    pointer ++;
}

Did you mean:

uint16_t* pointer = (unit16_t*)ataInfo;
uint16_t word;
for (int i = 0; i < 256; i++)
{
    word = inw(DATA_PORT);
    *pointer = word;
    pointer ++;
}

Upvotes: 1

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