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Topic: c programming question, malloc/free functions< Next Oldest | Next Newest >
Lii Offline





Group: Members
Posts: 7
Joined: Nov. 2004
Posted: Feb. 20 2005,07:26 QUOTE
can someone clear something for me, please?
let's say I have the following code:

1:  int main(){
2:  SomeFunction();
3:  return 0;}
4:
5:  int SomeFunction(){
6:  char *ptr;
7:  ptr=(char *)malloc(sizeof(char)*20);
8:  //...do something with ptr
9:  free(ptr);
10: return 0;}

my question is: what happens if I don't use the free(ptr) on line 9? When is the memory deallocated?

-When I return from the SomeFunction function on line 10?
-When I exit the program on line 3?
-Never?
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clacker Offline





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Posts: 570
Joined: June 2004
Posted: Feb. 20 2005,23:35 QUOTE
Lii, when you leave out the free memory isn't freed, ever.  This is known as a "memory leak."

When you exit the function memory can't be freed by default, what if another function needed that memory and you put the pointer into a global variable?
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Lii Offline





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Posts: 7
Joined: Nov. 2004
Posted: Feb. 21 2005,06:18 QUOTE
Quote (clacker @ Feb. 20 2005,18:35)
Lii, when you leave out the free memory isn't freed, ever.  This is known as a "memory leak."

When you exit the function memory can't be freed by default, what if another function needed that memory and you put the pointer into a global variable?

that's really sad!???

thx for your time.
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clacker Offline





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Posted: Feb. 21 2005,11:58 QUOTE
not that sad, I mean it causes crashes and all, but memory leaks are all gone when you restart the machine, so it isn't really "never" it's until restart.
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3 replies since Feb. 20 2005,07:26 < Next Oldest | Next Newest >

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