"Smart" (ish) pointer in C

I am a programmer with a primarily Rust-based background who has nonetheless taken an interest in C lately due to its simplicity and minimalism. However, one of the things I miss most from Rust is safe memory management. So I created a "smart pointer" of sorts to replicate that experience:

#include <stdio.h>/* This is a "smart" pointer thatuses Option types for safe memory management.*/typedef enum option {    Some,    None} Option;typedef struct OptionPointer {    void *content;    Option state;    int is_malloc;} OptionPointer;union internal_PointerType {    void *content;    int err;};typedef struct PointerType {    int choice;    union internal_PointerType internal;} PointerType;OptionPointer create_ptr(void *content, int is_malloc) {    OptionPointer p;    p.content = content;    p.state = Some;    p.is_malloc = is_malloc;    return p;}void set_ptr_invalid(OptionPointer *ptr) {    ptr->state = None;    // Only need to free memory    // if it was dynamically allocated,    // otherwise we only need to worry    // about dangling pointers    if (ptr->is_malloc) {        free(ptr->content);    }}PointerType get_ptr(OptionPointer *ptr) {    PointerType res;    res.choice = 0;    if (ptr->state == None) {        res.choice = 0;        res.internal.err = 1;    } else {        res.choice = 1;        res.internal.content = ptr->content;    }    return res;}// Exampleint main() {    char *a = "This is some testing text";    OptionPointer ptr = create_ptr(a, 0);    // Imaginary scenario where the pointer becomes invalid    set_ptr_invalid(&ptr);    PointerType res = get_ptr(&ptr);    if (res.choice) {        char *content = (char*)res.internal.content;        printf("%s\n", content);    } else {        printf("Invalid pointer at %s:%d\n", __FILE__, __LINE__);    }}

I can already see some notable problems:

• I literally just started programming in C a few days ago so I probably am not using recommended best practices
• "Smart" only goes so far - you'd have to call set_ptr_invalid()every single time a pointer could become invalid as a result of an operation
• This (possibly?) might not work well with malloc() and doesn't cover the case that malloc() wasn't successful

All feedback on this would be much appreciated!