 re_config(?Term)
re_config(?Term)Name(Value). Name is derived from the
PCRE_CONFIG_* constant after removing PCRE_CONFIG_ 
and mapping the name to lower case, e.g. utf8, unicode_properties, 
etc. Value is a Prolog boolean, integer, or atom. For boolean (1 or 0) 
values, true or false is returned.
re_config/1 will backtrack through all the possible configuration values if its argument is a variable. If an unknown option is specified, re_config/1 fails.
Non-compatible changes between PCRE1 and PCRE2 because numeric values 
changed: bsr and newline have been replaced by bsr2 
and
newline2:
bsr2 - previously bsr returned 0 or 1; now 
returns unicode or anycrlfnewline2 - previously newline returned an 
integer, now returns cr, lf, crlf, any, anycrlf, nulTerm values are as follows. Some values might not exist, depending on the version of PCRE2 and the options it was built with.
\R escape 
sequence matches by default. Replaces bsr option from 
PCRE1, which is not compatible.true if just-in-time compiling is available.cr, lf, crlf, any,
anycrlf, nul). Replaces newline 
option from PCRE1, which is not compatible.trueunicodeFor backwards compatibility with PCRE1, the following are accepted, but are deprecated:
utf8 - synonym for unicodelink_size - synonym for linksizematch_limit - synonym for matchlimitparens_limit - synonym for parenslimitunicode_properties - always trueThe following have been removed because they don't exist in PCRE2 and don't seem to have any meaningful use in PCRE1:
posix_malloc_thresholdmatch_limit_recursion