Re: mcedit issues

[Roland Illig <roland illig gmx de>]

Andrew V. Samoilov wrote:
> Also as far as I remember glib 1.2 allocates initially 1K memory area on default
> and doubles this area each time to fit string.  I am using LiveCD and
> embeded distros on low memory machines with specially stripped mc,
> so I dont glad to see this memory allocation strategy.

Yes, you're correct. I just checked glib-1.2, too.

We can argue about which strategy of allocation (glib, strcats() or 
n*strlen + m) is better/worse, but I don't think it makes much 
difference. Additionally, the string is freed in the same function call, 
so it is really temporary.

I wrote a little test program for the glib-1.2 memory usage. You should 
not use glib-1.2 at all if your memory is limited.

break = 0x8049924 (init)
break = 0x806b000 (after g_malloc)
break = 0x806a000 (after g_free)
break = 0x806a000 (after g_string_new)
break = 0x806a000 (after g_string_free)

Here you see that glib allocates quite much memory, and that it does not 
matter if we use GString or not.

Roland

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

#include <glib.h>

static void ps(const char *s)
{
    fprintf(stderr, "break = %p (%s)\n", sbrk(0), s);
}
    
int main(void)
{
    GString *s;
    void *p;
    ps("init");
    p = g_malloc(100);
    ps("after g_malloc");
    g_free(p);
    ps("after g_free");
    s = g_string_new("foo");
    ps("after g_string_new");
    g_string_free (s, TRUE);
    ps("after g_string_free");
    return 0;
}