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Hello,

I have come across the following directive but I don't see a class
name specified in front of the ::Check function. Does anyone
know what this means and how the directive is supposed to work?

#define TEST2(aValue, aExpected) ::Check(aValue, aExpected, __LINE__)

Thanks,

JG

John Goche wrote:
> Hello,
>
> I have come across the following directive but I don't see a class
> name specified in front of the ::Check function. Does anyone
> know what this means and how the directive is supposed to work?
>
> #define TEST2(aValue, aExpected) ::Check(aValue, aExpected, __LINE__)

::Check is a function in the global namespace.

Cheers! --M

mlimber wrote:
> John Goche wrote:
>
>>Hello,
>>
>>I have come across the following directive but I don't see a class
>>name specified in front of the ::Check function. Does anyone
>>know what this means and how the directive is supposed to work?
>>
>>#define TEST2(aValue, aExpected) ::Check(aValue, aExpected, __LINE__)
>
>
> ::Check is a function in the global namespace.
>

Can it be used for functions in the nameless namespace? Or is it more
for global functions?

For example:

#include <iostream>
using namespace std;

namespace
{
void f()
{
cout<<"222222222222"<<endl;
}
}

int main()
{
::f();
}

This will print 2's

VJ wrote:
> mlimber wrote:
>> John Goche wrote:
>>
>>> Hello,
>>>
>>> I have come across the following directive but I don't see a class
>>> name specified in front of the ::Check function. Does anyone
>>> know what this means and how the directive is supposed to work?
>>>
>>> #define TEST2(aValue, aExpected) ::Check(aValue, aExpected,
>>> __LINE__)
>>
>>
>>>> Check is a function in the global namespace.
>>
>
> Can it be used for functions in the nameless namespace? Or is it more
> for global functions?

Yes, it can. Unnamed/nameless/anonymous namespace names are inserted
into the scope in which that namespace appears. The way anonymous
namespace

// some scope
namespace {
// some names declared
}

behaves is similar to

// some scope
namespace SomeWeIrD_and_UNIQUEnaME {}
using namespace SomeWeIrD_and_UNIQUEnaME;
namespace SomeWeIrD_and_UNIQUEnaME {
// some names declared
}

(see 7.3.1.1/1); only the weird and unique name is different for
every translation unit and is *not* available to the programmer.

>
> For example:
>
> #include <iostream>
> using namespace std;
>
> namespace
> {
> void f()
> {
> cout<<"222222222222"<<endl;
> }
> }
>
> int main()
> {
> ::f();
> }
>
> This will print 2's

.... As it should.

V
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