gistfile1.txt

BF_tuple = Record.make_c_struct([
   ('w', double),
   ('h', uint64),
   ('pi', uint64),
])

src = """
typedef struct BF_tuple {
    double    w;
    uint64_t  h;
    uint64_t pi;
} BF_tuple;

typedef double (*bf_lmin)(BF_tuple*);
"""

f = FFI()
f.cdef(src)

data = f.new('BF_tuple[1]')
ptr = f.cast('BF_tuple*', data)

ptr[0].w = 0.1
ptr[0].h = 0
ptr[0].pi = 1

from numba import cffi_support

cffi_support.map_type(f.typeof('BF_tuple'), use_record_dtype=True)

sig = cffi_support.map_type(f.typeof('bf_lmin'), use_record_dtype=True)

from numba import cfunc, carray

@cfunc(sig)
def bf_lmin(z_):
    z = carray(z_, 1)[0]
    return z.w
    
#    if (x[0].w[0] < y.w
#        or (x.w == y.w and x.h < y.h)
#        or (x.w == y.w and x.h == y.h and x.pi < y.pi)):
#        if (z != x): 
#            z[0] = x[0]
#    else:
#        z[0] = y[0]


addr = int(f.cast('size_t', ptr))
print("address of data:", hex(addr))
bf_lmin.ctypes(addr)