Static memory allocation patterns in Embedded C - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is static memory allocation in embedded C?

Static memory allocation means reserving memory at compile time before the program runs. The size and location of memory are fixed and do not change during execution.

beginner

How does static memory allocation differ from dynamic memory allocation?

Static memory allocation reserves memory at compile time with fixed size, while dynamic memory allocation reserves memory at runtime and can change size during execution.

beginner

Give an example of static memory allocation in embedded C.

Example: <br>

int buffer[100]; // Array of 100 integers allocated statically

This array size and memory location are fixed at compile time.

intermediate

Why is static memory allocation preferred in embedded systems?

Because embedded systems often have limited memory and no operating system, static allocation avoids runtime overhead and fragmentation, making programs more predictable and reliable.

intermediate

What are common static memory allocation patterns in embedded C?

Common patterns include:<br>- Global variables<br>- Static local variables<br>- Fixed-size arrays<br>- Constant data in read-only memory<br>These ensure memory is reserved at compile time.

Which of the following is an example of static memory allocation?

A int *ptr = malloc(50 * sizeof(int));

B int arr[50];

C Using realloc() to resize memory

D Allocating memory inside a function with malloc

int arr[50]; allocates memory at compile time (static). malloc() and realloc() allocate memory at runtime (dynamic).

Why is static memory allocation safer in embedded systems?

A It requires an operating system

B It allows flexible memory resizing

C It uses more CPU cycles

D It avoids runtime memory fragmentation

Static allocation avoids fragmentation and unpredictable behavior because memory is fixed at compile time.

Which keyword in C declares a variable with static storage duration inside a function?

A static

B register

C auto

D extern

The 'static' keyword inside a function keeps the variable alive for the program's lifetime with fixed memory.

What happens if you declare a global array in embedded C?

A Memory is allocated statically at compile time

B Memory is not allocated until first use

C Memory is allocated on the stack

D Memory is allocated dynamically at runtime

Global variables and arrays are allocated statically at compile time in embedded C.

Which of these is NOT a benefit of static memory allocation in embedded systems?

A Predictable memory usage

B No runtime allocation overhead

C Ability to resize memory dynamically

D Avoids memory fragmentation

Static allocation cannot resize memory dynamically; that is a feature of dynamic allocation.

Explain static memory allocation and why it is important in embedded C programming.

Think about how embedded devices have limited memory and no OS.

List common static memory allocation patterns used in embedded C and describe their purpose.

Consider where memory is reserved before the program runs.