10.3 Regular Expression Matching

The GNU C library supports two interfaces for matching regular expressions. One is the standard POSIX.2 interface, and the other is what the GNU system has had for many years.

Both interfaces are declared in the header file regex.h. If you define _POSIX_C_SOURCE, then only the POSIX.2 functions, structures, and constants are declared.

• POSIX Regexp Compilation: Using regcomp to prepare to match.
• Flags for POSIX Regexps: Syntax variations for regcomp.
• Matching POSIX Regexps: Using regexec to match the compiled pattern that you get from regcomp.
• Regexp Subexpressions: Finding which parts of the string were matched.
• Subexpression Complications: Find points of which parts were matched.
• Regexp Cleanup: Freeing storage; reporting errors.