Re: NewPtr vs malloc
Re: NewPtr vs malloc
- Subject: Re: NewPtr vs malloc
- From: Brendan Younger <email@hidden>
- Date: Sat, 8 Dec 2001 16:21:31 -0500
On Saturday, December 8, 2001, at 03:57 PM, Tomas Zahradnicky, Jr.
wrote:
On Thursday, December 6, 2001, at 10:12 am, Joe Chang (l %l ,m8)
wrote:
Hi all,
I'm wondering if there are differences between NewPtr and malloc,
DisposePtr and free. Which ones are better? or just same?
They are both the same, i would use malloc vs NewPtr, since its more
standard (exact same code will work everywhere)
Althrough they might seem the same, they are not. ptr = NewPtr(size) is
mac os toolbox function which allocates free pointer block. You may
want to allocate ptr = NewPtrClear(size) --- a cleared pointer block.
You can get size of that block GetPtrSize(ptr) or tell user why the
allocation failed err = MemError() right after a call to NewPtr. You
may also resize the block using SetPtrSize and MemError afterwards.
However, all these have equivalents.
NewPtr = malloc
NewPtrClear = calloc
GetPtrSize = malloc_size
SetPtrSize = realloc
and MemError() is not needed as badly on a system with good virtual
memory. If the pointer is nil, there is simply no memory to be had.
As far as actual implementation details, NewPtr currently calls malloc
and DisposePtr calls free and I would assume the other functions did the
same.
Brendan Younger