defer_free

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>

#define CONCAT_(a,b) a##b
#define CONCAT(a,b) CONCAT_(a,b)

// Should they fault or ignore on 0?
// Make a more safe cast function.
struct DeferFreeStruct{
    void **memory;
    ~DeferFreeStruct()
    {
        printf("Close: %s", *memory);
        free(*memory);
    }
};

struct DeferFcloseStruct{
    FILE **file;
    ~DeferFcloseStruct()
    {
        printf("Close File\n");
        fclose(*file);
    }
};

#define defer_free(memory_pointer) \
DeferFreeStruct CONCAT(defer_free_unique_name_, __COUNTER__) = {(void **)&(memory_pointer)}
#define defer_fclose(file_handle) \
DeferFcloseStruct CONCAT(defer_fclose_unique_name_, __COUNTER__) = {file_handle}

char *read_file(char *file_name)
{
    FILE *file = fopen(file_name, "rb");
    assert(file);
    defer_fclose(&file);
    fseek(file,0,SEEK_END);
    size_t file_size = ftell(file);
    rewind(file);
    char *file_data = (char *)malloc(file_size + 1);
    assert(file_data);
    fread(file_data, 1, file_size, file);
    file_data[file_size] = 0;
    
    return file_data;
}

int main() {
    char *vera = 0;
    defer_free(vera);
    vera = (char *)calloc(8,1);
    for(int i = 0; i < 8; ++i)
    {
        vera[i] = "testor\n"[i];
    }
    char *some_file = read_file("SomeFile.txt");
    defer_free(some_file);
    
    printf(vera);
    printf(some_file);
    
    
    
    return 0;
}