I have a struct I'm accessing via ctypes:
struct attrl {
char *name;
char *resource;
char *value;
struct attrl *next;
enum batch_op op;
};
So far I have Python code like:
# struct attropl
class attropl(Structure):
pass
attrl._fields_ = [
("next", POINTER(attropl)),
("name", c_char_p),
("resource", c_char_p),
("value", c_char_p),
But I'm not sure what to use for the batch_op
enum. Should I just map it to a c_int
or ?
At least for GCC enum
is just a simple numeric type. It can be 8-, 16-, 32-, 64-bit or whatever (I have tested it with 64-bit values) as well as signed
or unsigned
. I guess it cannot exceed long long int
, but practically you should check the range of your enum
s and choose something like c_uint
.
Here is an example. The C program:
enum batch_op {
OP1 = 2,
OP2 = 3,
OP3 = -1,
};
struct attrl {
char *name;
struct attrl *next;
enum batch_op op;
};
void f(struct attrl *x) {
x->op = OP3;
}
and the Python one:
from ctypes import (Structure, c_char_p, c_uint, c_int,
POINTER, CDLL)
class AttrList(Structure): pass
AttrList._fields_ = [
('name', c_char_p),
('next', POINTER(AttrList)),
('op', c_int),
]
(OP1, OP2, OP3) = (2, 3, -1)
enum = CDLL('./libenum.so')
enum.f.argtypes = [POINTER(AttrList)]
enum.f.restype = None
a = AttrList(name=None, next=None, op=OP2)
assert a.op == OP2
enum.f(a)
assert a.op == OP3