I''m really curious about something... When you declare templates, you can do things like: template int test() { return N; } And it compiles just fine; but when you replace the int with a float or double it doesn''t compile O_o. Why is this?

quote:Original post by Puzzler183
I'm really curious about something... When you declare templates, you can do things like:

template int test()
{
return N;
}

And it compiles just fine; but when you replace the int with a float or double it doesn't compile O_o. Why is this?

Because a non-type template parameter must be of one of the following

— an integral constant-expression of integral or enumeration type; or
— the name of a non-type template-parameter; or
— the name of an object or function with external linkage, including function templates and function
template-ids but excluding non-static class members, expressed as id-expression; or
— the address of an object or function with external linkage, including function templates and function
template-ids but excluding non-static class members, expressed as & id-expression where the & is
optional if the name refers to a function or array; or
— a pointer to member

As specified in 14.3.2 of the C++ standard

[edited by - Jingo on November 29, 2003 8:40:30 PM]

quote:Original post by Jingo

Because a non-type template parameter must be of one of the following

— an integral constant-expression of integral or enumeration type; or
— the name of a non-type template-parameter; or
— the name of an object or function with external linkage, including function templates and function
template-ids but excluding non-static class members, expressed as id-expression; or
— the address of an object or function with external linkage, including function templates and function
template-ids but excluding non-static class members, expressed as & id-expression where the & is
optional if the name refers to a function or array; or
— a pointer to member

As specified in 14.3.2 of the C++ standard

[edited by - Jingo on November 29, 2003 8:40:30 PM]

But you didn''t answer my question... I know the standard says so, but why? What is the point of restricting things like that?

Link

I have been enlightened (although it still seems kinda pointless), thankyou!