The 'DEF' statement is deprecated

[jwilk]

When building with Cython 3.0.0b1, I get a few warnings like this:

afl.pyx:40:0: The 'DEF' statement is deprecated and will be removed in a future Cython version. Consider using global variables, constants, and in-place literals instead. See cython/cython#4310

These are the affected lines:

DEF SHM_ENV_VAR = b'__AFL_SHM_ID'
DEF FORKSRV_FD = 198
DEF MAP_SIZE_POW2 = 16
DEF MAP_SIZE = 1 << MAP_SIZE_POW2

[jwilk]

I've tried this:

cdef extern from *:
    # These constants must be kept in sync with afl-fuzz:
    '''
    #define SHM_ENV_VAR "__AFL_SHM_ID"
    #define FORKSRV_FD 198
    #define MAP_SIZE_POW2 16
    #define MAP_SIZE (1 << MAP_SIZE_POW2)
    '''
    extern const char *SHM_ENV_VAR
    extern int FORKSRV_FD
    extern int MAP_SIZE

It didn't quite work…
The docstring-for-extern works only since Cython 0.28 (cython/cython#1915), but we still support 0.19.

[jwilk]

Ubuntu 18.04 LTS (supported until April 2023) ships with Cython 0.26.1.