Thread: Embedded system link list

Hello Everyone

I am working on an embedded system wherein I have limited available space. I know there is a dynamic memory allocation available for link list creation but I want to create a link list using static memory allocation. Dynamic memory allocation leads to or may lead to leaks if multiple dynamic allocations takes place. I am not sure, however there is a big possibility that if memory management is not handled in a static manner, may lead to leaks and crush especially in embedded system.
So I wanted to know if anyone has any suggestion as to how to create a link list using static memory management. The system needs to create c link list by adding an element to the link list(if the element is already present then discard the element).

Code:

typedef struct node;
struct node
{
   uint8_t id;
   struct node *next;
}

Thanks to everyone.

How big do you expect your data to grow? Perhaps it is feasible to simply use an array of fixed size.

The first thing you should consider if you're on a memory constrained embedded system is a linked list the best "container" for the job. Even if you have perfect memory allocation/de-allocation a dynamic list can still consume all available memory in a memory constrained system because it will grow to the size needed. You need to constrain this growth to a known limit.

Perhaps a simple statically allocated array is all you need.


Jim

Hello Matticus and jimblumberg,

Thank you for your reply.
Yes my embedded system is under memory constraints. I am looking for max #(uint8_t id)=200.

Code:

typedef uint8_t RecvId[8];typedef struct node;

struct node

{

   Recv id;

   struct node *next;

}

add_id()
{
//
}

search_id()
{
//
}

int main()
{
add_id();//adds an id to the link list
search();//returns a node if an id already exist

   return 0;
}

This is a base for my code without malloc. Thanks again

Why do you think you need a linked list?

What exactly are you trying to accomplish?

I really really suggest you reconsider you approach. Think about a statically allocated array instead.



Jim

If you're just using a static array, you don't need a "next" pointer.

In fact, if the only data you need is "id", then you don't even need a struct.

jimblumberg My goal is to receive an id which is of 8byte ,prepended with a "key" of 3 byte ,received in a buffer. once i receive this buffer, I add this id info into my link list . I have to also check if the id already exists. If it does exist, i drop the id and wait for another Id. as there are other struct members , therefore, i used struct. And I thought link list would serve my purpose. If there is any better suggestion i am open to it as long as i dont have to worry about malloc replacement for the embedded system.

Matticus Would you like to elaborate on your point. Thankkss