16
Library introduction
[library]
16.4
Library-wide requirements
[requirements]
16.4.5
Constraints on programs
[constraints]
16.4.5.3
Reserved names
[reserved.names]
16.4.5.3.6
User-defined literal suffixes
[usrlit.suffix]
1
#
Literal suffix identifiers (
[over.
literal]
) that do not start with an underscore are reserved for future standardization
.
Literal suffix identifiers that contain a double underscore
__
are reserved for use by C++ implementations
.