- Version Information — variables and functions to check the GLib version
- Basic Types — standard GLib types, defined for ease-of-use and portability
- Standard Macros — commonly-used macros
- Type Conversion Macros — portably storing integers in pointer variables
- Byte Order Macros — a portable way to convert between different byte orders
- Bounds-checking integer arithmetic — a set of helpers for performing checked integer arithmetic
- Numerical Definitions — mathematical constants, and floating point decomposition
- Miscellaneous Macros — specialized macros which are not used often
- Atomic Operations — basic atomic integer and pointer operations