I've found that the following sample, which uses nothrow memory allocation
semantics, generates a segmentation violation:
// g++ -g -fcheck-new -fno-exceptions -fno-rtti sample.cpp
#include <stdlib.h>
class foo {
public:
int v;
foo(){ v = 0; }
~foo() {}
void* operator new[](size_t size) {
return 0; // simulated memory failure
}
void operator delete[](void* p, size_t size) { }
};
main()
{
foo *p = new foo[2];
// p==4 here
if (p) delete [] p;
return 0;
}
The segmentation violation results from a bug in the code that is generated
to call operator new[]. The return of operator new[] is correctly checked
for non-zero before calling the ctor ("-fcheck-new" semantics), but this
return value is subsequently incremented by 4. As a result, p is set to 4
(not 0) when memory runs out.
A work around is to modify applications so that the return value of "new
class[]" is checked and to treat a return of 4 the same as 0.
Tom
--
Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
Problem reports: http://cygwin.com/problems.html
Documentation: http://cygwin.com/docs.html
FAQ: http://cygwin.com/faq/
