| pointers--avoiding a memory leak [message #39425] |
Wed, 19 May 2004 12:20 |
MKatz843
Messages: 98
Registered: March 2002
|
Member |
|
|
Here's a simple Pointers 101 question for the pointer gurus.
Suppose you have a structure with a pointer field
s = {a:10, b:ptr_new(10)}
Somewhere down the line you want to update the value of *s.b making it
equal to the value contained in a another pointer, say *q = 20. After
the assignment, you'll no longer need the q pointer.
So which is a better strategy?
#1)
ptr_free, s.b
s.b = q
#2)
*s.b = *q
ptr_free, q
#3)
s.b = q ;--- what becomes of the old s.b in this case?
I can see how #1 is memory-efficient because only the pointer is
passed. I can see that #2 is memory inefficient because the values are
swapped. This could be slower if the value is a large array. I can see
how #3 might result in a memory leak, since the old s.b value could be
stranded in memory with no pointer pointing to it. Am I right about
these? What else should I be thinking about in the above situation?
Thanks,
M. Katz
|
|
|
|
comp.lang.idl-pvwave archive
Members
Search
Help
Login
Home
