cpp/regex/match results/format

outputs a format string, replacing any format specifiers or escape sequences in that string with match data from.

@1@ The format character sequence is defined by the range. The resulting character sequence is copied to. @2@ The format character sequence is defined by the characters in. The resulting character sequence is copied to. @3-4@ The format character sequence is defined by the characters in and  respectively. The resulting character sequence is copied to a newly constructed std, which is returned.

The bitmask determines which format specifiers and escape sequences are recognized.

The behavior of is undefined if.

Return value
@1-2@ @3-4@ The newly constructed string containing resulting character sequence.