From the C standard, section 7.1.3:
- All identifiers that begin with an underscore and either an uppercase letter or another underscore are always reserved for any use.
- All identifiers that begin with an underscore are always reserved for use as identifiers with file scope in both the ordinary and tag name spaces.
The internal struct which defines each container used to start with an underscore followed by a lower case letter. The leading underscore for those identifiers have been replaced in order to prevent undefined behaviour.
