I am getting error while clearing the array
I want to copy all the data of some variables from the MySettings structure
struct Block {
int id;
};
struct MySettings {
int conf_id;
int group;
int enable;
int hide_name;
int login_persistence;
int remove_cache;
struct Block *block;
};
struct MySettings *Settings[50];
void clear(void) {
puts("Clearing...");
for(int i = 0; i < 50; i++) {
if(Settings[i]) {
if(Settings[i]->block)
free(Settings[i]->block);
free(Settings[i]);
Settings[i] = NULL;
}
}
}
int GetGroupID(int i)
{
return i;
}
void read_db(void) {
puts("Allocating...");
for(int i = 0; i < 10; i++) {
struct MySettings *st = calloc(1, sizeof *st);
st->conf_id = i;
st->hide_name = 1;
st->login_persistence = 1;
st->remove_cache = 1;
st->block = realloc(st->block, (i + 1) * sizeof *st->block);
st->block[i].id = i+1;
for(int g = 0; g < 5; g++) {
st->group = GetGroupID(g);
st->enable = 1;
printf("pointer %p group_id %d enable %s\n", st, st->group, st->enable ? "true" : "false");
Settings[st->group] = st;
}
}
clear();
}
int main(void)
{
read_db();
puts("Done...");
return 0;
}
In the group and enable part, I look for a way for each entry to have a different address
What currently happens is that when I do the for loop using variable g all group and enable generated in this loop have the same address
I want group and enable to always have different addresses
What should I do ?
This is possible and even easy to do
When you set Settings[st->group] = st, the loop will always use the same address.
To create an address at each exit of the for loop we need to create a new structure
As for the double free issue, we need to create a separate settings cleaning to avoid this type of problem
Here's the example, based on your code:
#include <stdio.h>
#include <stdlib.h>
struct Block {
int id;
};
struct config {
int conf_id;
int hide_name;
int login_persistence;
int remove_cache;
struct Block *block;
};
struct MySettings {
int group;
int enable;
struct config *conf;
};
struct config *conf[50];
struct MySettings *Settings[50];
void clear(void) {
puts("Cleaning...");
for(int i = 0; i < 50; i++) {
if(conf[i]) {
if(conf[i]->block)
free(conf[i]->block);
free(conf[i]);
conf[i] = NULL;
}
if(Settings[i]) {
free(Settings[i]);
Settings[i] = NULL;
}
}
}
int GetGroupID(int i)
{
return i;
}
void read_db(void) {
puts("Allocating...");
for(int i = 0; i < 10; i++) {
struct config *config = calloc(1, sizeof *conf);
config->conf_id = i;
config->hide_name = 1;
config->login_persistence = 1;
config->remove_cache = 1;
config->block = realloc(config->block, (i + 1) * sizeof *config->block);
config->block[i].id = i+1;
for(int g = 0; g < 5; g++) {
struct MySettings *st = calloc(1, sizeof *st);
st->group = GetGroupID(g);
st->enable = 1;
st->conf = config;
printf("pointer %p pointer conf %p group_id %d enable %s\n", st, st->conf, st->group, st->enable ? "true" : "false");
Settings[st->group] = st;
}
conf[config->conf_id] = config;
}
clear();
}
int main(void)
{
read_db();
puts("Done...");
return 0;
}
I have the following output from this code:
Allocating...
pointer 0x55e6ed1d62b0 pointer conf 0x55e6ed1d6270 group_id 0 enable true
pointer 0x55e6ed1d62d0 pointer conf 0x55e6ed1d6270 group_id 1 enable true
pointer 0x55e6ed1d62f0 pointer conf 0x55e6ed1d6270 group_id 2 enable true
pointer 0x55e6ed1d6310 pointer conf 0x55e6ed1d6270 group_id 3 enable true
pointer 0x55e6ed1d6330 pointer conf 0x55e6ed1d6270 group_id 4 enable true
pointer 0x55e6ed1d6390 pointer conf 0x55e6ed1d6350 group_id 0 enable true
pointer 0x55e6ed1d63b0 pointer conf 0x55e6ed1d6350 group_id 1 enable true
pointer 0x55e6ed1d63d0 pointer conf 0x55e6ed1d6350 group_id 2 enable true
pointer 0x55e6ed1d63f0 pointer conf 0x55e6ed1d6350 group_id 3 enable true
pointer 0x55e6ed1d6410 pointer conf 0x55e6ed1d6350 group_id 4 enable true
pointer 0x55e6ed1d6470 pointer conf 0x55e6ed1d6430 group_id 0 enable true
pointer 0x55e6ed1d6490 pointer conf 0x55e6ed1d6430 group_id 1 enable true
pointer 0x55e6ed1d64b0 pointer conf 0x55e6ed1d6430 group_id 2 enable true
pointer 0x55e6ed1d64d0 pointer conf 0x55e6ed1d6430 group_id 3 enable true
pointer 0x55e6ed1d64f0 pointer conf 0x55e6ed1d6430 group_id 4 enable true
pointer 0x55e6ed1d6550 pointer conf 0x55e6ed1d6510 group_id 0 enable true
pointer 0x55e6ed1d6570 pointer conf 0x55e6ed1d6510 group_id 1 enable true
pointer 0x55e6ed1d6590 pointer conf 0x55e6ed1d6510 group_id 2 enable true
pointer 0x55e6ed1d65b0 pointer conf 0x55e6ed1d6510 group_id 3 enable true
pointer 0x55e6ed1d65d0 pointer conf 0x55e6ed1d6510 group_id 4 enable true
pointer 0x55e6ed1d6630 pointer conf 0x55e6ed1d65f0 group_id 0 enable true
pointer 0x55e6ed1d6650 pointer conf 0x55e6ed1d65f0 group_id 1 enable true
pointer 0x55e6ed1d6670 pointer conf 0x55e6ed1d65f0 group_id 2 enable true
pointer 0x55e6ed1d6690 pointer conf 0x55e6ed1d65f0 group_id 3 enable true
pointer 0x55e6ed1d66b0 pointer conf 0x55e6ed1d65f0 group_id 4 enable true
pointer 0x55e6ed1d6710 pointer conf 0x55e6ed1d66d0 group_id 0 enable true
pointer 0x55e6ed1d6730 pointer conf 0x55e6ed1d66d0 group_id 1 enable true
pointer 0x55e6ed1d6750 pointer conf 0x55e6ed1d66d0 group_id 2 enable true
pointer 0x55e6ed1d6770 pointer conf 0x55e6ed1d66d0 group_id 3 enable true
pointer 0x55e6ed1d6790 pointer conf 0x55e6ed1d66d0 group_id 4 enable true
pointer 0x55e6ed1d6800 pointer conf 0x55e6ed1d67b0 group_id 0 enable true
pointer 0x55e6ed1d6820 pointer conf 0x55e6ed1d67b0 group_id 1 enable true
pointer 0x55e6ed1d6840 pointer conf 0x55e6ed1d67b0 group_id 2 enable true
pointer 0x55e6ed1d6860 pointer conf 0x55e6ed1d67b0 group_id 3 enable true
pointer 0x55e6ed1d6880 pointer conf 0x55e6ed1d67b0 group_id 4 enable true
pointer 0x55e6ed1d68f0 pointer conf 0x55e6ed1d68a0 group_id 0 enable true
pointer 0x55e6ed1d6910 pointer conf 0x55e6ed1d68a0 group_id 1 enable true
pointer 0x55e6ed1d6930 pointer conf 0x55e6ed1d68a0 group_id 2 enable true
pointer 0x55e6ed1d6950 pointer conf 0x55e6ed1d68a0 group_id 3 enable true
pointer 0x55e6ed1d6970 pointer conf 0x55e6ed1d68a0 group_id 4 enable true
pointer 0x55e6ed1d69e0 pointer conf 0x55e6ed1d6990 group_id 0 enable true
pointer 0x55e6ed1d6a00 pointer conf 0x55e6ed1d6990 group_id 1 enable true
pointer 0x55e6ed1d6a20 pointer conf 0x55e6ed1d6990 group_id 2 enable true
pointer 0x55e6ed1d6a40 pointer conf 0x55e6ed1d6990 group_id 3 enable true
pointer 0x55e6ed1d6a60 pointer conf 0x55e6ed1d6990 group_id 4 enable true
pointer 0x55e6ed1d6ad0 pointer conf 0x55e6ed1d6a80 group_id 0 enable true
pointer 0x55e6ed1d6af0 pointer conf 0x55e6ed1d6a80 group_id 1 enable true
pointer 0x55e6ed1d6b10 pointer conf 0x55e6ed1d6a80 group_id 2 enable true
pointer 0x55e6ed1d6b30 pointer conf 0x55e6ed1d6a80 group_id 3 enable true
pointer 0x55e6ed1d6b50 pointer conf 0x55e6ed1d6a80 group_id 4 enable true
Clearing...
Done...
This should work as expected