Crash Course: configuration
Table of Contents
EnTT doesn't offer many hooks for customization but it certainly offers
In the vast majority of cases, users will have no interest in changing the default parameters. For all other cases, the list of possible configurations with which it's possible to adjust the behavior of the library at runtime can be found below.
All options are intended as parameters to the compiler (or user-defined macros
within the compilation units, if preferred).
Each parameter can result in internal library definitions. It's not recommended to try to also modify these definitions, since there is no guarantee that they will remain stable over time unlike the options below.
EnTT is designed in such a way that it works (almost) everywhere out of the
box. However, this is the result of many refinements over time and a compromise
regarding some optimizations.
It's worth noting that users can get a small performance boost by passing this definition to the compiler when the library is used in a standalone application.
The purpose of this parameter is to suppress the use of
noexcept by this
To do this, simply define the variable without assigning any value to it.
hashed_string class introduces the
_hws suffixes to accompany
its user defined literals.
In the case of conflicts or even just to change these suffixes, it's possible to do so by associating new ones with these definitions.
EnTT doesn't offer primitives to support multi-threading. Many of
the features can be split over multiple threads without any explicit control and
the user is the only one who knows if and when a synchronization point is
However, some features aren't easily accessible to users and can be made thread-safe by means of this definition.
entt::id_type is directly controlled by this definition and widely used within
By default, its type is
std::uint32_t. However, users can define a different
default type if necessary.
As is known, the ECS module of
EnTT is based on sparse sets. What is less
known perhaps is that these are paged to reduce memory consumption in some
The default size of a page is 32kB but users can adjust it if appropriate. In all case, the chosen value must be a power of 2.
For performance reasons,
EnTT doesn't use exceptions or any other control
structures. In fact, it offers many features that result in undefined behavior
if not used correctly.
To get around this, the library relies on a lot of
asserts for the purpose of
detecting errors in debug builds. However, these assertions may in turn affect
performance to an extent.
This option is meant to disable all controls.
In order to reduce memory consumption and increase performance, empty types are
never stored by the ECS module of
Use this variable to treat these types like all others and therefore to create a dedicated storage for them.
After many adventures,
EnTT finally works fine across boundaries.
To do this, the library mixes some non-standard language features with others that are perfectly compliant.
This definition will prevent the library from using non-standard techniques, that is, functionalities that aren't fully compliant with the standard C++.