Strange behavior in IOS while integrating with a c/c++ library.
In AppDelegate i call
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND,0), ^{
[[ABCService sharedInstance] abcInitialize];
});
abcInitialize is defined in c++ library
struct abc *top;
top = calloc(TYPE_SERV,size_of(struct abc));
top->us = server_alloc (...certain_params...);
inside server alloc i do alloc of structures struct1 and struct2 And then in Initialize function i try to access
top->us = calloc(TYPE_US, size_of(struct us));
if(top->us->struct1) //do something
I noticed that my struct1 is always null
When i debugged, i can see that the structure was allocated fine and values are set appropriately, but before returning from the function, the memory is automatically deallocated. This is totally confusing and annoying. Could any one help me understand what is going on?
I tried by turning off ARC too, still no change
top->us = calloc(TYPE_US, size_of(struct us)); if(top->us->struct1) //do somethingI noticed that my struct1 is always null
If that's your real code, then yes, struct1 will always be null. calloc allocates memory and initializes it to zero. Hence, all of the members of top->us will be zero, and since struct1 is a member of top->us, it's going to be zero, i.e. NULL.
First of all, ARC has nothing to do with memory management of C or C++ codes, so, you can rule out ARC for causing this.
According to http://www.cplusplus.com/reference/cstdlib/calloc/, calloc always initialize all the bits of the allocated memory to 0, naturally, top->us->struct1 will be NULL.
but before returning from the function, the memory is automatically deallocated
How do you come to the conclusion that the memory is automatically deallocated? As mentioned above, ARC will not automatically release your C++ structure/object.
As a conclusion. The result you saw was indeed as expected.
I found the issue and it was due to linking the same file twice from different library. I have corrected my libraries and that had fixed my issue. So no source code was updated. Just the libs were corrected with the right sources. Thanks a lot of for your support.