convenient & saf

automatic-memory-management.c

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

// most code is single-threaded
unsigned char* current_mem;

void* readA();
void* readB();

void* auto_alloc(size_t size) {
    unsigned char* result = current_mem;
    current_mem += size;
    return (void*)result;
}

void* automanage(void* (*f)(void)) {
    // pretty much all the memory you'll ever need
    unsigned char mem[5000];
    unsigned char* prev_mem = current_mem;
    current_mem = mem;
    void* result = f();
    current_mem = prev_mem;
    return result;
}

int main(int argc, char* argv[]) {
    puts("Enter two lines");
    automanage(readA);
    return EXIT_SUCCESS; // darn right
}

void* readA() {
    char* input = auto_alloc(80);
    gets(input); // no segmentation faults if you go past 80 - p. cool

    automanage(readB);

    printf("readA got: %s\n", input);

    return NULL;
}

void* readB() {
    char* input = auto_alloc(80);
    gets(input);

    printf("readB got: %s\n", input);

    return NULL;
}