A regular expression search mechanism is available with C compilers. It is usually implemented as a library or by macros, but differs in the functionality and interface. To avoid a system dependence an own finite state regular expression search machine has been adopted from a public domain source. The string with the regular expression is parsed for wildcards and known special characters list in Table A.1.
Tabelle A.1: Special characters in regular expressions
A compiled regular expression can be matched against a string. The library returns the start and end of the maximum match from the regular expression and the input string for further processing.