""" Python 2.7.11 garbage collector bug code snippet """
import ctypes
import gc

my_Library_Name = "clib_filename.so"
MAX_LIST_COUNT = 50

# load the c-library
cdll.LoadLibrary(my_Library_Name)

# define c-structure:
# (please don't comment on the c-structure this was done this
#  way a long time ago to support something else and had to be
#  done this way for that particular architecture - no need to
#  discuss why it has to be this way)
class pyStruct_cstruct1_t(ctypes.Structure):
    _fields_ = [ ("red_cats", c_int16),
                 ("blu_dogs", c_int16),
                 ("red_x", (c_int16 * 2)),
                 ("blu_x", (c_int16 * 2)),
                 ("red_P", (c_int16 * 4)),
                 ("blu_P", (c_int16 * 4)),
                 ("avar", c_int16),
                 ("ivar", c_int16),
                 ("s1var", c_int),
                 ("s2var", c_int8) ]

class pyStruct_cstruct2_t(ctypes.Structure):
    _fields_ = [ ("list", (pyStruct_cstruct1_t \
                    * MAX_LIST_COUNT)),
                 ("free", (POINTER(pyStruct_cstruct1_t) \
                    * MAX_LIST_COUNT)),
                 ("used", (POINTER(pyStruct_cstruct1_t) \
                    * MAX_LIST_COUNT)),
                 ("free_count", c_int8),
                 ("used_count", c_int8) ]


#### temporary workaround -- allows it to work consistently
# gc.disable()

cvar_mystruct2 = pyStruct_cstruct2_t()
cvar_mystruct1 = pyStruct_cstruct1_t()
cvar_mystruct1.red_cats = my_redcat
cvar_mystruct1.blu_dogs = my_bludog
cvar_myother_struct1 = pyStruct_cstruct1_t()

for j in range(0, len(my_other_cats)):
    cvar_myother_struct1 = pyStruct_cstruct1_t()
    cvar_myother_struct1.red_cats = c_int16(my_other_cats[j])
    cvar_myother_struct1.blu_dogs = c_int16(my_other_dogs[j])
    cvar_mystruct2.used[j] = pointer(cvar_myother_struct1)

cvar_retstatus = c_int32(-9999)
cvar_someothervar = c_int32(0)

# C-library function call  (gets NULL pointer - causes segmentation fault)
# seems the garbage collector is cleaning house because of the local scope
# of the for loop on linux platform but not on mac platform. The behavior
# across platforms is not consistent. (same python version on both platforms).
cvar_retstatus = ctypes.myclib.mycfunction( \
    byref(cvar_mystruct1), byref(cvar_mystruct2), cvar_someothervar )

# other code that works with the result from the c-function
# not included here

#### temporary workaround -- allows it to work consistently
# gc.enable()


##EOF##