Thread: Question about array pointer

Hi all,

I am a bit confused on how to use array pointers.

What I want to do is to fill a predefined region starting from a known memory location.

I thought of doing something like that:

Code:

/*
 * I want to fill the region from
 * [0xa00000000 - 0xA00000400) with zeros
 */

uint32_t *Array_A[100] = (uint32_t*)0xA000000;


for (count=0; count<100; count++)
{
        Array_A[count]=0;
}

Unfortunately, the above doesn't seem to work as expected.

Could anyone tell me what I am doing wrong?


Thanks a lot in advance.

Hi and thanks for you reply

Originally Posted by quzah

Pointing pointers at random spots in memory is usually a bad idea. It hasn't been a really good idea for 15 years or more.

It's not really random, I know which memory region to use but in general you're right.

Originally Posted by quzah

Anyway, you have an array of pointers, and you are trying to assign the whole thing a value at once, which you can't do.

I don't really get where I am trying to do that...

With that

Code:

uint32_t *Array_A[100] = (uint32_t*)0xA000000;

I am just making the array pointer to point at 0xA000000 and then I am trying to set a single location at a time with the loop.

Originally Posted by quzah

Why don't you just use something like memset if you want to specify a value to copy everywhere?

I don't actually have lib support and I would like to do it just with array pointers if possible.

Thanks.

Code:

uint32_t *Array_A[100] = (uint32_t*)0xA000000;

I am just making the array pointer to point at 0xA000000 and then I am trying to set a single location at a time with the loop.

Unless you are working on an imbedded system and that's a microcontroller addres this is a Bad Idea... a real bad idea!

If you're just trying to build an array... use malloc() that's what it's for.