PCRE stands for Perl-compatible regular expression library. PCRE has its own native API, but a set of "wrapper" functions that are based on the POSIX API are also supplied in the library libpcreposix. Note that this just provides a POSIX calling interface to PCRE: the regular expressions themselves still follow Perl syntax and semantics. The header file for the POSIX-style functions is called pcreposix.h.
The library is available as 32-bit and 64-bit:
Current version: v8.40-1