The second _io_BufferedWriter_write_impl call is for show warning like
"ResourceWarning: unclosed file <_io.BufferedRandom name='myfile'>"
Try `f.close()`, or `with open(...)`.
On Thu, May 30, 2019 at 12:03 PM Windson Yang <wiwind...@gmail.com> wrote:
>
> My script looks like this:
>
> f = open('myfile', 'a+b')
> f.write(b'abcde')
>
> And I also add a `printf` statement in the _io_BufferedWriter_write_impl
> <https://github.com/python/cpython/blob/ada319bb6d0ebcc68d3e0ef2b4279ea061877ac8/Modules/_io/bufferedio.c#L1910>
> function.
>
> static PyObject * _io_BufferedWriter_write_impl(buffered *self,
> Py_buffer *buffer)
> /*[clinic end generated code: output=7f8d1365759bfc6b
> input=dd87dd85fc7f8850]*/
> {
> printf("call write_impl\n");
> PyObject *res = NULL;
> Py_ssize_t written, avail, remaining;
> Py_off_t offset;
> ...
>
> After I compiled then run my script. I found _io_BufferedWriter_write_impl
> <https://github.com/python/cpython/blob/ada319bb6d0ebcc68d3e0ef2b4279ea061877ac8/Modules/_io/bufferedio.c#L1910>
> had
> been called twice which I expected only once. The second time it changed
> self->pos to an unexpected value too.
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--
Inada Naoki <songofaca...@gmail.com>
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