Lawrence D'Oliveiro <[EMAIL PROTECTED]> wrote:
> In message <[EMAIL PROTECTED]>, Gabriel
> Genellina wrote:
>
>> ... a python string has both a length *and* a null terminator (for
>> ease of interfacing C routines ...
>
> How does that work for strings with embedded nulls? Or are the C routines
> simply fooled into seeing a truncated part of the string?
>
If passed to a C library function it would mean that the C code would
generally only use up to the first embedded null. However the Python
standard library will usually check for nulls first so it can throw an
error:
>>> with open('test.txt', 'r') as f:
... print f.read()
...
Hello world
>>> with open('test.txt\x00junk', 'r') as f:
... print f.read()
...
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: file() argument 1 must be (encoded string without NULL
bytes), not str
>>>
What actually happens is that Python argument parsing code will reject
values with embedded nulls if asked to convert a parameter to a C string
('s', 'z', 'es', or 'et' formats), but will allow them if converting to a C
string and a length ('s#', 'z#', 'es#', or 'et#').
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