How do I build a python string from a raw (binary) ctype buffer?

Question

I'm playing with Python and ctypes and I can't figure out how to resolve this problem. I call to a C function which fills a raw binary data. My code looks like this: ``` class Client(): def __init__(self): self.__BUFSIZE = 1024*1024 self.__buf = ctypes.create_string_buffer(self.__BUFSIZE) self.client = ctypes.cdll.LoadLibrary(r"I:\bin\client.dll") def do_something(self): len_written = self.client.fill_raw_buffer(self.__buf, self.__BUFSIZE) my_string = repr(self.__buf.value) print my_string ``` The problem is that I'm receiving binary data (with 0x00) and it's truncated when I tried to build my_string. How can I build my_string if self._buf contains null bytes 0x00? Any idea is welcome. Thanks

Accepted Answer

You can access a buffer returned by `create_string_buffer()` as a Python string by using its `raw` attribute:

```
a = ctypes.create_string_buffer(10)
a.raw 
# '\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
```

To only access the first `n` bytes, use

```
a.raw[:n]
```

How do I build a python string from a raw (binary) ctype buffer?

Solution

Problem