Narrow Vs. wide streams

[Dave]

The program below is conforming according to VC++ 7.1 and Comeau online. I
would have expected a type mismatch. Am I seeing a compiler problem, or is
the observed behavior correct?

Thanks!


#include <iostream>

using namespace std;

int main()
{
// Displays a hex number under VC++ 7.1
cout << L"Hello world!" << endl;

// Displays "Hello world!" under VC++ 7.1
wcout << "Hello world!" << endl;
}

 

[Jonathan Turkanis]

Your operator<< call calls a method of the form

Imp &operator<<(const void *p_val)

in both cases.

In the first case only: narrow C-style strings can be written to any
basic_ostream: chars are widened using a ctype facet.

The subsequent "translation" from void * to char * or
w_char * is handled by the stream, and is independent from
what p_val originally pointed to (as far as I understand).

Jonathan

 

[Efrat Regev]

The program below is conforming according to VC++ 7.1 and Comeau online. I
would have expected a type mismatch. Am I seeing a compiler problem, or is
the observed behavior correct?

Thanks!


#include <iostream>

using namespace std;

int main()
{
// Displays a hex number under VC++ 7.1
cout << L"Hello world!" << endl;

// Displays "Hello world!" under VC++ 7.1
wcout << "Hello world!" << endl;
}

Your operator<< call calls a method of the form

Imp &operator<<(const void *p_val)

in both cases. The subsequent "translation" from void * to char * or w_char
* is handled by the stream, and is independent from
what p_val originally pointed to (as far as I understand).

 

[Efrat Regev]

In the first case only: narrow C-style strings can be written to any
basic_ostream: chars are widened using a ctype facet.


Jonathan

Yes, you're right. Sorry for my mistaken reply.