API and ABI Versioning

CPython exposes its version number in the following macros. Note that these correspond to the version code is built with, not necessarily the version used at run time.

See C API Stability for a discussion of API and ABI stability across versions.

PY_MAJOR_VERSION

The 3 in 3.4.1a2.

PY_MINOR_VERSION

The 4 in 3.4.1a2.

PY_MICRO_VERSION

The 1 in 3.4.1a2.

PY_RELEASE_LEVEL

The a in 3.4.1a2. This can be 0xA for alpha, 0xB for beta, 0xC for release candidate or 0xF for final.

PY_RELEASE_SERIAL

The 2 in 3.4.1a2. Zero for final releases.

PY_VERSION_HEX

The Python version number encoded in a single integer.

The underlying version information can be found by treating it as a 32 bit number in the following manner:

Bytes	Bits (big endian order)	Meaning	Value for 3.4.1a2
1	1-8	PY_MAJOR_VERSION	0x03
2	9-16	PY_MINOR_VERSION	0x04
3	17-24	PY_MICRO_VERSION	0x01
4	25-28	PY_RELEASE_LEVEL	0xA
	29-32	PY_RELEASE_SERIAL	0x2

Thus 3.4.1a2 is hexversion 0x030401a2 and 3.10.0 is hexversion 0x030a00f0.

All the given macros are defined in Include/patchlevel.h.