python调用libpcap

python调用ctypes库和libpcap库报错

import libpcap as pcap
import ctypes as ct

errbuf = ct.create_string_buffer(pcap.PCAP_ERRBUF_SIZE + 1)
device = pcap.lookupdev(errbuf)

pd = pcap.open_live(device,65535,0,1000,errbuf)

fcode = pcap.bpf_program()
localnet = pcap.bpf_u_int32()
netmask = pcap.bpf_u_int32()
handle = pcap.open_live(device, 65535, 1, 1000, errbuf)
filter = bytes(str('port 80'), 'ascii')
buf = ct.c_char_p(filter)

pcap.compile(handle,ct.byref(fcode),buf,ct.c_int(1),netmask)

报错 OSError: exception: access violation reading 0x0000000000000018

检查查询发现最后一步函数加粗的变量提示指针方面的问题但无解决方法

求解决谢谢