templated function default argument that does nothing

[Hicham Mouline]

Hello,

I have a function template whose arguments specify policy inside a tight
loop

struct DefaultPolicy {
void operator()(...)
{
}
};


struct OtherPolicy{
void operator()(...)
{
// do something
}
};

template <typename T1, typename Policy>
void f( const T1& t1, const Policy& policy = DefaultPolicy() )
{

for (...)
for (...)
{
// get first result
policy ( result );
}
}

}


so that the user can call f without specifying the template arguments,
just the T1 arg, and sometimes the policy arg too.

Ideally, the policy ( result ) call would be totally optimized away by the
compiler if it's the default one.

Does this seem a reasonable pattern?

regards,

 

[SG]

Hello,

I have a function template whose arguments specify policy inside a tight
loop
[...]

Does this seem a reasonable pattern?

Does it even work? I don't think so.

Cheers!
SG

 

[Hicham Mouline]

Hello,

I have a function template whose arguments specify policy inside a tight
loop
[...]

Does this seem a reasonable pattern?

Does it even work? I don't think so.

Cheers!
SG

Turns out I have to specify the template argument Policy in all cases, even
if I want the default.
Also, function template cannot have default args.

Nevertheless, how about the optimization away questions?

regards,

 

[red floyd]

Hello,
I have a function template whose arguments specify policy inside a tight
loop

[...]

Does this seem a reasonable pattern?

Does it even work? I don't think so.

Cheers!
SG

Turns out I have to specify the template argument Policy in all cases, even
if I want the default.
Also, function template cannot have default args.

Nevertheless, how about the optimization away questions?

I believe Alexandrescu uses this pattern in MC++D.