What's the difference between `DOREPLIFETIME_WITH_PARAMS_FAST` and `DOREPLIFETIME_WITH_PARAMS`?

Development Programming & Scripting C++
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1

What’s the difference between DOREPLIFETIME_WITH_PARAMS_FAST and DOREPLIFETIME_WITH_PARAMS ?

Here is the definition of DOREPLIFETIME_WITH_PARAMS_FAST:

#define DOREPLIFETIME_WITH_PARAMS_FAST(c,v,params) \
{ \
	static const bool bIsValid_##c_##v = ValidateReplicatedClassInheritance(StaticClass(), c::StaticClass(), TEXT(#v)); \
	const TCHAR* DoRepPropertyName_##c_##v(TEXT(#v)); \
	const NetworkingPrivate::FRepPropertyDescriptor PropertyDescriptor_##c_##v(DoRepPropertyName_##c_##v, (int32)c::ENetFields_Private::v, 1); \
	RegisterReplicatedLifetimeProperty(PropertyDescriptor_##c_##v, OutLifetimeProps, params); \
}

and here is the definition of DOREPLIFETIME_WITH_PARAMS:

#define DOREPLIFETIME_WITH_PARAMS(c,v,params) \
{ \
	FProperty* ReplicatedProperty = GetReplicatedProperty(StaticClass(), c::StaticClass(),GET_MEMBER_NAME_CHECKED(c,v)); \
	RegisterReplicatedLifetimeProperty(ReplicatedProperty, OutLifetimeProps, params); \
}

Whats fast about the fast version? Why would I ever use the nonfast version?

2

in the chain call of the DOREPLIFETIME_WITH_PARAMS_FAST I can’t see property validation for the replication flag (CPF_Net).

I think that you can choose DOREPLIFETIME_WITH_PARAMS_FAST when you absolutely know that your property is marked as Replicated. and to avoid relative function calls.

3

That seems reasonable. (I would of called it _UNCHECKED or _UNSAFE instead of _FAST to make this clearer.) Do you know what happens if you use the fast version with a property that is not marked Replicated ?

4

I just tested and it did not compile.

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image1405×88 4.44 KB

5

The _FAST version doesn’t compile if the property doesn’t have a Replicated flag? Are you sure? If so, then I don’t understand why anyone would ever use the nonfast version.

6

Yes, I also got an intellisense error before compiling, the tooltip didn’t show in the video I’ll post an image below.

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image986×399 29.3 KB

7

until both versions (fast and nonfast) don’t compile without Replicated or ReplicatedUsing - you can use only fast version :slight_smile: