20
Library introduction
[library]
20.5
Library-wide requirements
[requirements]
20.5.4
Constraints on programs
[constraints]
20.5.4.3
Reserved names
[reserved.names]
20.5.4.3.5
User-defined literal suffixes
[usrlit.suffix]
1
#
Literal suffix identifiers (
[over.literal]
) that do not start with an underscore are reserved for future standardization
.