31 May
2005
31 May
'05
4:12 p.m.
Hello,
I don't know what realloc() does, the code looks like this
while (size > 0) {
interface->altsetting = realloc(interface->altsetting, sizeof(struct
usb_interface_descriptor) *
(interface->num_altsetting + 1));
if (!interface->altsetting) {
if (usb_debug >= 1)
fprintf(stderr, "couldn't malloc interface->altsetting\n");
return -1;
}
....
}
So I was wonder is its extend or just allocating a new block of memory?
Kind regards
Rene W. Olsen
31 May
31 May
3:53 p.m.
Hi,
Rene W. Olsen wrote:
I don't know what realloc() does, the code looks
like this
while (size > 0) {
interface->altsetting = realloc(interface->altsetting, sizeof(struct
usb_interface_descriptor) *
(interface->num_altsetting + 1));
if (!interface->altsetting) {
if (usb_debug >= 1)
fprintf(stderr, "couldn't malloc interface->altsetting\n");
return -1;
}
....
}
So I was wonder is its extend or just allocating a new block of memory?
Both.
If the original pointer is NULL, it is equivalent to a malloc. If it's
not, it will re-allocate the block, and the contents will remain the
same (up to min(oldsize, newsize)).
If size is zero, it's equivalent to a free.
Note that it does not necessarily operate in-place. It might also
allocate at a new address, and copy the contents.
Here's a link to the manpage: http://www.rt.com/man/realloc.3.html
Regards,
--
Thomas Frieden <ThomasF(a)hyperion-entertainment.biz>
Hyperion Entertainment
- Naur dan i-deryg lhuin
5:09 p.m.
On 2005/05/31, Thomas Frieden wrote:
okey thanks
Regards
Rene W. Olsen
So I was
wonder is its extend or just allocating a new block of memory?
Both.
If the original pointer is NULL, it is equivalent to a malloc. If it's
not, it will re-allocate the block, and the contents will remain the
same (up to min(oldsize, newsize)).
If size is zero, it's equivalent to a free.
Note that it does not necessarily operate in-place. It might also
allocate at a new address, and copy the contents.
Here's a link to the manpage: http://www.rt.com/man/realloc.3.html
25 Jun
25 Jun
6:47 p.m.
On 2005/05/31, Thomas Frieden wrote:
I have been trying to use exec's realloc and my resoult looks like this
APTR my_realloc(
struct LibusbBase *libBase,
APTR mem,
uint32 size )
{
struct LibusbBase *libBase;
APTR retval;
libBase = (struct LibusbBase *)Self->Data.LibBase;
if ( mem )
{
retval = libBase->lib_IExec->AllocVec( size, MEMF_CLEAR|MEMF_PUBLIC );
}
else
{
libBase->lib_IExec->ReallocVec( mem, size, MEMF_CLEAR|MEMF_PUBLIC );
retval = mem;
}
return( retval );
}
But I not really sure this is ok, what happens if reallocvec() need to alloc a new block
and move
the memory? how do I get the new mem pointer?
Regards
Rene W. Olsen
So I was
wonder is its extend or just allocating a new block of memory?
Both.
If the original pointer is NULL, it is equivalent to a malloc. If it's
not, it will re-allocate the block, and the contents will remain the
same (up to min(oldsize, newsize)).
If size is zero, it's equivalent to a free.
Note that it does not necessarily operate in-place. It might also
allocate at a new address, and copy the contents.
Here's a link to the manpage: http://www.rt.com/man/realloc.3.html
5:55 p.m.
Hi,
Rene W. Olsen wrote:
But I not really sure this is ok, what happens if
reallocvec() need to alloc a new block and move the memory? how do I get the new mem
pointer?
Exec's ReallocVec does not move memory, it will resize in place if there
is enough room, otherwise it will fail.
Regards,
--
Thomas Frieden <ThomasF(a)hyperion-entertainment.biz>
Hyperion Entertainment
- Naur dan i-deryg lhuin
6:57 p.m.
On 2005/06/25, Thomas Frieden wrote:
Hi,
Rene W. Olsen wrote:
Ohh okey, but isent it a really big chance it fails?
if yes, I have to make my own realloc that moves it every time.
Regards
But I not really sure this is ok, what happens if
reallocvec() need to alloc a new block and move
the memory? how do I get the new mem pointer?
Exec's ReallocVec does not move memory, it will resize in place if there
is enough room, otherwise it will fail.
6:28 p.m.
Hi,
Rene W. Olsen wrote:
Ohh okey, but isent it a really big chance it fails?
Yes. The thing is, a "normal" realloc (i.e. allocate a new block and
copy) is simple to do. Hoewever, resizing the block isn't.
if yes, I have to make my own realloc that moves it
every time.
I'd recommend that, anyway. In the current system ReallocVec is still a
bit broken.
Regards,
--
Thomas Frieden <ThomasF(a)hyperion-entertainment.biz>
Hyperion Entertainment
- Naur dan i-deryg lhuin
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