Re: Memory issues.

After looking at this post, I think I now understand the difference between
static and non-static better. I modified mine to use static instead, so that
it doesn't re-allocate all the time. What is the chance of it being
 overwritten before it's done being used?

 - Valnir

> ----- Original Message ----- 
> From: "Dennis" <[email protected]>
> To: <[email protected]>
> Sent: Wednesday, April 06, 2005 11:06 PM
> Subject: RE: Memory issues.
>
>
>> His function won't allocate anything at boot time.
>>
>> If you look close, you'll notice he is using
>>
>>  char command_string[MSL];
>>
>> which will allocate memory on the stack when the function is called, not
>>
>>  static char command_string[MSL];
>>
>> The only difference in the two functions is that one allocates memory
>> on the heap and one on the stack.
>> The heap alloacation will take a little bit longer (more work to do),
>> while the stack allocation will use up space on the stack (Get too many 
>> of those MSL buffers on the stack at the same time and you'll have some 
>> problems.  I'm guessing that's why the original
>> function didn't use the stack).
>>
>>
>> Dennis
>>
>>
>> On Wed, 6 Apr 2005, Richard Lindsey wrote:
>>
>>> Well, the memory for that allocation won't be freed before it's done
>>> being used, as do_function will wait for the function to return before
>>> freeing that chunk, at which point it's done being used... if, for some
>>> reason, the function being called were to free the memory internally
>>> before returning to do_function, then you would just get a warning in
>>> your log that free_string tried to free an invalid size of <whatever>...
>>> your revised function looks like it would be ok as well, except that it
>>> will allocate the memory for command_string at boot time, even if
>>> do_function was never called during gameplay... the current method
>>> ensures that memory is only allocated for the command_string if
>>> do_function is called... since it's only 1 variable that's MSL in size,
>>> it won't really impact performance any, as tons of do_func's allocate
>>> multiple variables of that size at boot time...
>>>
>>> Richard Lindsey.
>>>
>>> -----Original Message-----
>>> From: [email protected] [mailto:[email protected]] On Behalf Of Valnir
>>> Sent: Wednesday, April 06, 2005 10:57 AM
>>> To: [email protected]
>>> Subject: Re: Memory issues.
>>>
>>> Well.. I think I found ONE of my problems.. It's in the function
>>> "do_function".
>>>
>>> /* function to keep argument safe in all commands -- no static strings
>>> */
>>> void do_function (CHAR_DATA *ch, DO_FUN *do_fun, char *argument)
>>> {
>>>    char *command_string;
>>>
>>>    /* copy the string */
>>>    command_string = str_dup(argument);
>>>
>>>    /* dispatch the command */
>>>    (*do_fun) (ch, command_string);
>>>
>>>    /* free the string */
>>>    free_string(command_string);
>>> }
>>>
>>> Umm.. is it just me, or does this seem a little wasteful to allocate
>>> memory
>>> that could get released before it's done being used? I also posted my
>>> REVISED version, please tell me if it makes more sense.
>>>
>>> /* function to keep argument safe in all commands -- no static strings
>>> */
>>> void do_function (CHAR_DATA *ch, DO_FUN *do_fun, char *argument)
>>> {
>>>    char command_string[MSL];
>>>
>>>    /* copy the string */
>>>    strcpy( command_string, argument );
>>>
>>>    /* dispatch the command */
>>>    (*do_fun) (ch, command_string);
>>> }
>>>
>>> - Valnir
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