PY_VERSION_HEX is the Python version number encoded in a single integer.
For example if the
PY_VERSION_HEX is set to
0x030401a2, 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
0xCfor release candidate and
0xFfor final), in this case it is alpha.
3.4.1a2, zero for final releases)
3.4.1a2 is hexversion
All the given macros are defined in Include/patchlevel.h.