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 C Library 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.