[Kamailio-Devel] Creating shared memory during runtime

[Iñaki Baz Castillo]

El Viernes, 9 de Enero de 2009, Daniel-Constantin Mierla escribió:
> Hello,
>
> no, it won't work. you have to allocate a pointer where to store the
> pointer.

Thanks a lot. Please let me some questions inline:


> char **address;
> char *string;
>
> static int mod_init(void)
> {
> 	address = shm_malloc(sizeof(char*));
> 	string = shm_malloc(sizeof(char) * 100);
> 	*address = string;
> 	// Store some value in 'string'.
> }
>
> static struct mi_root* mi_function(struct mi_root* cmd_tree, void* param) {
> 	string = *address;
          ^------------ why is this needed? 'string' already was '*address'.

> 	shm_free(string);
> 	string = shm_malloc(sizeof(char) * 200);
> 	*address = string;
> 	// Store some new value in 'string'.
> }


If I'm not wrong, the memory after mod_init() and the memory after 
mi_function() would be something as:


Memory after mod_init():
----------------------------------------------------------
1000 | pointer 'address' | "4000"


4000 | pointer 'string'  | "hello world"
...  | 
4099 |


----------------------------------------------------------



Memory after mi_function():
----------------------------------------------------------
1000 | pointer 'address' | "7000"





7000 | pointer 'string' | "hello again, now I'm longer!"
...  |
...  |
...  |
...  |
7199 |

----------------------------------------------------------



This means that when a process wants to read 'string' value (*string) they 
must access it via *address value (**address), is it?


Thanks a lot.


-- 
Iñaki Baz Castillo