Re: Running out of memory on stack in C++ routine invoked within Cocoa NSOperation
Re: Running out of memory on stack in C++ routine invoked within Cocoa NSOperation
- Subject: Re: Running out of memory on stack in C++ routine invoked within Cocoa NSOperation
- From: "Clark S. Cox III" <email@hidden>
- Date: Wed, 18 Feb 2009 09:07:45 -0800
I would strongly reccommend using std::vector instead of a raw array.
That way you're immune from stack size issues.
Sent from my iPhone
On Feb 18, 2009, at 0:31, Leo Singer <email@hidden> wrote:
Actually, if the big array and the loop are moved from the C++ method
into the Objective C selector - (void) main then the same
EXEC_BAD_ACCESS occurs. So the problem is not related to C++. The
following source code still exhibits the same problem:
//////////////// TestOperation.h /////////////////////
#import <Cocoa/Cocoa.h>
@interface TestOperation : NSOperation {
}
@end
//////////////// End of TestOperation.h /////////////////////
//////////////// TestOperation.mm /////////////////////
#import "TestOperation.h"
@implementation TestOperation
- (void) main
{
int bigArray[256000];
for (int j = 0 ; j < 256000 && ![self isCancelled] ; j ++)
{
bigArray[j] = 2*j;
}
}
@end
//////////////// End of TestOperation.mm /////////////////////
On Wed, Feb 18, 2009 at 3:16 AM, Leo Singer <email@hidden>
wrote:
Hi,
I have a C++ method that I am invoking from within the - (void) main
selector of an NSOperation. My Cocoa application is crashing because
this particular C++ method puts a huge amount of data on the
stack. I
am getting an EXEC_BAD_ACCESS error. However, the same C++ routine
works fine if I call it from within a command line C++ program.
I have contrived some sample code to illustrate the problem.
TestOperation is an (Objective C) subclass of NSOperation; I am
running the NSOperation in a separate thread by putting it into an
NSOperationQueue. TestOperationImpl is a C++ class. The NSOperation
is responsible for doing one thing only: calling the go() method on
an
instance of TestOperationImpl.
Note the very large array of ints that is declared inside
TestOperationImpl::go(). If it is changed to an array of shorts or
an
array of chars, then this example code works fine, no
EXEC_BAD_ACCESS.
Is there any way for me to give my application more memory, or at
least give more memory to the thread that is running this C++ method?
Thanks,
Leo
//////////////// TestOperation.h /////////////////////
#import <Cocoa/Cocoa.h>
class TestOperationImpl {
private:
bool cancelled;
public:
TestOperationImpl();
void go();
void cancel();
};
@interface TestOperation : NSOperation {
TestOperationImpl* testOpImpl;
}
- initWithController: (TestOperationController*) controller;
@end
//////////////// End of TestOperation.h /////////////////////
//////////////// TestOperation.mm /////////////////////
#import "TestOperation.h"
TestOperationImpl::TestOperationImpl(TestOperationController*
controller)
: cancelled(false)
{
}
void TestOperationImpl::go()
{
int bigArray[256000];
for (int j = 0 ; j < 256000 && !cancelled ; j ++)
{
bigArray[j] = 2*j;
}
}
void TestOperationImpl::cancel()
{
cancelled = true;
}
@implementation TestOperation
- initWithController: (TestOperationController*) ctrl
{
if (self = [self init])
testOpImpl = new TestOperationImpl(ctrl);
controller = ctrl;
return self;
}
- (void) dealloc
{
delete testOpImpl;
[super dealloc];
}
- (void) cancel
{
testOpImpl->cancel();
[super cancel];
}
- (void) main
{
testOpImpl->go();
}
@end
//////////////// End of TestOperation.mm /////////////////////
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