How to activate the extended GNAT Ada superset (GNAT Reference Manual)

### 17.1 How to activate the extended GNAT Ada superset ¶

There are two ways to activate the extended GNAT Ada superset:

- The Pragma Extensions_Allowed. To activate the curated set of extensions, you should use

    pragma Extensions_Allowed (On)

As a configuration pragma, you can either put it at the beginning of a source file, or in a `.adc` file corresponding to your project.

- The `-gnatX` command-line option will activate the curated subset of extensions.

Attention: You can activate the experimental set of extensions in addition by using either the `-gnatX0` command-line option, or the pragma `Extensions_Allowed` with `All_Extensions` as an argument. However, it is not recommended you use this subset for serious projects; it is only meant as a technology preview for use in playground experiments.