- String Utility Functions — various string-related functions
- Character Set Conversion — convert strings between different character sets
- Unicode Manipulation — functions operating on Unicode characters and UTF-8 strings
- Base64 Encoding — encodes and decodes data in Base64 format
- Data Checksums — computes the checksum for data
- Secure HMAC Digests — computes the HMAC for data
- Internationalization — gettext support macros
- Date and Time Functions — calendrical calculations and miscellaneous time stuff
- GTimeZone — a structure representing a time zone
- GDateTime — a structure representing Date and Time
- Random Numbers — pseudo-random number generator
- Hook Functions — support for manipulating lists of hook functions
- Miscellaneous Utility Functions — a selection of portable utility functions
- Lexical Scanner — a general purpose lexical scanner
- Timers — keep track of elapsed time
- Spawning Processes — process launching
- File Utilities — various file-related functions
- URI Functions — manipulating URIs
- Hostname Utilities — Internet hostname utilities
- Shell-related Utilities — shell-like commandline handling
- Commandline option parser — parses commandline options
- Glob-style pattern matching — matches strings against patterns containing '*' (wildcard) and '?' (joker)
- Perl-compatible regular expressions — matches strings against regular expressions
- Regular expression syntax — syntax and semantics of regular expressions supported by GRegex
- Simple XML Subset Parser — parses a subset of XML
- Key-value file parser — parses .ini-like config files
- Bookmark file parser — parses files containing bookmarks
- Testing — a test framework
- UNIX-specific utilities and integration — pipes, signal handling
- Windows Compatibility Functions — UNIX emulation on Windows