c - Python: How to pack different types of data into a string buffer using struct.pack_into -

i'm trying pack unsigned int data string buffer created using ctypes.create_string_buffer.

here following code segment, , running example showing error on codepad:

import struct import ctypes import binascii  buf = ctypes.create_string_buffer(16) struct.pack_into("=i=i=i", buf, 0, 1, 2, 3) print binascii.hexlify(buf) 

this yields following error:

... struct.error: bad char in struct format 

the documentation doesn't allude whether can pack data of different types if underlying buffer of specific c type. in case, trying pack unsigned int data string buffer underlying c_char type. know of solution this, or there specific way create buffer can pack type of data?

you're not supposed prefix every output specifier '=' code. once:

struct.pack_into("=iii", buf, 0, 1, 2, 3) 

this yields:

01000000020000000300000000000000