C++ - nothrow

This constant value 'nothrow' is used as an argument for operator new and operator new[] to indicate that these functions shall not throw an exception on failure, but return a null pointer instead. By default, when the new operator is used to allocate memory and the handling function is unable to do so, a 'bad_alloc' exception is thrown. But when nothrow is used as argument for new , it returns a null pointer instead.

 

 

#include <iostream>

 

using namespace std;

 

int

main ()

{

    try

    {

        char * p = new char [1000];

    }

    catch (bad_alloc& e)

    {

        cerr << "bad_alloc caught: " << e.what() << endl;

    }

 

    return 0;

}

 

==>

 

#include <iostream>

 

using namespace std;

 

int main ()

{

    char * p = new (nothrow) char [1000];

    if (p==0)

    {

        cout << "Failed!/n" ;

    }

    else

    {

        cout << "Success!/n" ;

        delete [] p;

    }

 

    return 0;

}