This package forms part of the Boost C++ Libraries collection.
Regular expressions are a form of pattern-matching that are often
used in text processing; many users will be familiar with the Unix
utilities grep, sed and awk, and the programming language perl, each
of which make extensive use of regular expressions. Traditionally C++
users have been limited to the POSIX C APIs for manipulating regular
expressions, and while regex does provide these APIs, they do not
represent the best way to use the library. For example regex can cope
with wide character strings, or search and replace operations (in a
manner analogous to either sed or perl), something that traditional C
libraries can not do.