Regex pattern matching
Regular expressions combine literal characters and metacharaters to define the search and replace criteria. You run the functions from the Informix® Regex extension to find matches to strings, replace strings, and split strings into substrings.
The Informix® Regex extension supports extended regular expressions, based on the POSIX 1003.2 standard, and basic regular expressions
You can specify case-sensitive or case-insensitive searching.
You can search single-byte character sets or UTF-8 character sets.
Henry Spencer's regular expression library
The Informix® Regex pattern matching utilizes Henry Spencer's regular expression library. Use of this library requires the following notice:
Copyright 1992, 1993, 1994, 1997 Henry Spencer. All rights reserved. This software is not subject to any license of the American Telephone and Telegraph Company or of the Regents of the University of California.
Permission is not granted to anyone to use this software for any purpose on any computer system, and to alter it and redistribute it, subject to the following restrictions:
1. The author is not responsible for the consequences of use of this software, no matter how awful, even if they arise from flaws in it.
2. The origin of this software must not be misrepresented, either by explicit claim or by omission. Since few users ever read sources, credits must appear in the documentation.
3. Altered versions must be plainly marked as such, and must not be misrepresented as being the original software. Since few users ever read sources, credits must appear in the documentation.
4. This notice may not be removed or altered.