22 General utilities library [utilities]

22.14 Formatting [format]

22.14.7 Formatting of ranges [format.range]

22.14.7.2 Class template range_formatter [format.range.formatter]

Table 76: Meaning of range-type options [tab:formatter.range.type]
Option
Requirements
Meaning
m
T shall be either a specialization of pair or a specialization of tuple such that tuple_size_v<T> is 2.
Indicates that the opening bracket should be "{", the closing bracket should be "}", the separator should be ", ", and each range element should be formatted as if m were specified for its tuple-type.
[Note 2: 
If the n option is provided in addition to the m option, both the opening and closing brackets are still empty.
— end note]
s
T shall be charT.
Indicates that the range should be formatted as a string.
?s
T shall be charT.
Indicates that the range should be formatted as an escaped string ([format.string.escaped]).