[Python-Dev] String views (was: Re: Proof of the pudding:str.partition()) (original) (raw)

Fredrik Lundh fredrik at pythonware.com
Fri Sep 2 08:36:45 CEST 2005

skip at pobox.com wrote:

Fredrik> Python strings are character buffers with a known length, not Fredrik> null-terminated C strings. the CPython implementation Fredrik> guarantees that the character buffer has a trailing NULL Fredrik> character, but that's mostly to make it easy to pass Python Fredrik> strings directly to traditional C API:s.

I'm obviously missing something that's been there all along. Since Python strings can contain NULs, why do we bother to NUL-terminate them? Clearly, any tradition C API that expects to operate on NUL-terminated strings would break with a string containing an embedded NUL.

sure, but that doesn't mean that such an API would break on a string that doesn't contain an embedded NUL.

in practice, this is the difference between the "s" and "s#" argument specifiers; the former requires a NUL-free string, the latter can handle any byte string:

>>> f = open("myfile\0")
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
TypeError: file() argument 1 must be (encoded string without NULL bytes), not str
>>> f = open("myfile")
>>> f
<open file 'myfile', mode 'r' at 0x0091E9A0>

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