Question

int *arr = (int*) malloc(100*sizeof(int));
int *arr_copy = (int*) malloc(100*sizeof(int));
srand(123456789L);
for( int i = 0; i < 100; i++) {
    arr[i] = rand();
    arr_copy[i] = arr[i];
}

// ------ do stuff with arr ------

// reset arr...
std::copy(arr_copy, arr_copy+100,  arr);

while compiling this I get this warning for std::copy():

c:\program files (x86)\microsoft visual studio 10.0\vc\include\xutility(2227):
warning C4996: 'std::_Copy_impl': Function call with parameters that may be
unsafe - this call relies on the caller to check that the passed values are 
correct. To disable this warning, use -D_SCL_SECURE_NO_WARNINGS. See 
documentation on how to use Visual C++ 'Checked Iterators'

I know how to disable/ignore the warning, but is there is a simple one liner solution to make a “checked iterator” out of an unchecked pointer? Something like (I know cout is not an unchecked pointer like int*, but just e.g.):

ostream_iterator<int>  out(cout," ");

std::copy(arr_copy, arr_copy+numElements,  out);

I don’t want to write a whole new specialized class my_int_arr_output_iterator : iterator.... But can I use one of the existing iterators?

—edit—

As there are many many questions abt my usage of c-style-arrays and malloc instead of STL containers, let me just say that I’m writing a small program to test different sorting algorithms’ performance and memory usage. The code snippet you see above is a specialized (original code is template class with multiple methods, testing one algorithm for different number of elements in arrays of different types) version specific to the problem.

In other words, I do know how to do this using STL containers (vector) and their iterators (vector::begin/end). What I didn’t know is what I asked.

Thanks though, hopefully someone else would benefit from the answers if not me.

Answer 1

The direct answer you’re looking for is the stdext::checked_array_iterator. This can be used to wrap a pointer and it’s length into a MSVC checked_iterator.

std::copy(arr_copy, arr_copy+100, stdext::checked_array_iterator<int*>(arr, 100) );

They also provide a stdext::checked_iterator which can wrap a non-checked container.