Hi all,
I am on lepord 10.5.7 . The following issue was also seen in 10.5.5 .
I am facing an issue with leaks utility in mac and would like your comments on the same .
I have introduced leaks explicitly in my xcode test case program through
char *p=(char*) malloc(1000*sizeof(char));
p=NULL;
As per the man pages of the leaks utility , it catches all leaked memory – memory that has been allocated but has been lost and cannot be freed . As in the above said case 1000 characters have been allocated and the only pointer to the said 1000 characters has been lost by p=NULL , I expected leaks to tell me this as a leak . However it did not .
Do we need to set any variable (environment ) etc to make leaks catch this error ?
I had set the environment variable by export MallocStackLogging=1 which is used for displaying stack trace AFTER it identifies a leak .
Has anyone else faced similar issues in the past or am I doing it the wrong way . Kindly comment .
Also I see that
1) Many a times leaks utility gives strange behavior , identifying leaks during a run and in subsequent runs of the same test program , not identifying leaks at all .
2) Identifying leaks only in function calls and not in main program .
3) Not identifying leaks at all in those cases where an external dll have been used .
Let me give you the sample code which I used test using leaks utility on mac .
Since it was not giving leaks with 1000 I increased it several times but still no help .
#include <iostream>
void callme()
{
char *p=(char *) malloc(1024*1024*sizeof(char));
}
int main (int argc, char * const argv[]) {
int i ;
std::cin >>i;
std::cout << "Hello, World!\n";
callme();
char *c =(char *) malloc(5000*sizeof(char));
c=(char *)malloc(5000*sizeof(char));
c=NULL;
std::cin >>i;
return 0;
}
1) This code fragment was compiled and then run . and attached to instrument’s leaks utility (during call of first scanf I attached the process with leaks utility) . It is clear that callme() will lead to memory leak . However the leaks utility identified it only once and during reruns of the same test program it failed to identify this as a leak .
2) During cases when leaks utility did identified it as a leak , it failed to identify leaks in main
char *c =(char *) malloc(5000*sizeof(char));
c=(char *)malloc(5000*sizeof(char));
c=NULL;
Note that since c is pointing to memory of character 5000 and later points to another 5000 different memory , we should get a leak in main also . However leak utility
failed to identify this as a leak .
Please note that we did set export MallocStackLogging=1 before running the program in the same terminal window
Has anyone else faced similar issues in the past or am I doing it the wrong way . Kindly comment .
Thanks and Regards
Manish