Hi Stefan,
Thanks for your suggestion.
First of all, I answer your question. I only want to capture the output&input
from python when I call py file or import a module in C/C++ code. It works
something like a debug output window does. I could only guess that Python uses
something like printf(). That's why I want to redirect the stdout/in.
Then, I have tried this method. It works. I got the text print from the file.
below are the code I used following your advice.
import sys
original = sys.stdout
sys.stdout = open('redirect.txt', 'w')
...
other code!
...
sys.stdout.close()
sys.stdout = original
But it still not exactly what I expected. Because the text printed to the file
can't be read into the program at the same time.
As you mentioned you are not familiar with Windows. I guess you are using
Linux. So could you give me some advice if it can be done in C/C++ in Linux?
Thanks again for your kind help.
Best Regards,
Jian
At 2017-07-20 22:34:35, "Stefan Seefeld" <ste...@seefeld.name> wrote:
>On 19.07.2017 23:25, Jian wrote:
>>
>> Dear Gurus,
>>
>> I want to embed python interpreter in my program. What I want is to
>> redirect those output to a control such as RICHEDIT which can be
>> modified as a output window in my program. So I can write *.py files
>> outside of program and invoke it inside program as a script file. In
>> order to get information output by the *.py file I need to get the
>> stdin&stdout. I have tried some workflow but not perfect.
>>
>
>So you want to capture all output produced by the Python session,
>without changing the behaviour of `std::cout` or `printf()`, correct ?
>
>> 1). I have tried use Allocconsle(). But I can only get the output info
>> printed by std::out & printf() in the current code. all things which
>> are printed by python35.dll are missing. I used print('xxxx') in the
>> *.py file to test the output. Those *.py files are OK in command line
>> mode.
>>
>> 2). I also tried to derive class basic_streambuf and overwrite the
>> in/out functions. It works only for output from std::out. Text from
>> printf() as well as from dlls are missing.
>>
>> 3). then I tried to use linker settings as below.
>>
>> #pragma comment( linker, "/subsystem:console /entry:wWinMainCRTStartup" )
>>
>> A cmd window is created along with the program. everything output from
>> current process and dlls are retrieved successfully as I want. But the
>> cmd window is not easy to control.
>>
>> Is there a better way for this purpose?
>>
>
>I suggest you import the `sys` module and substitute `sys.stdout` and
>`sys.stderr` to capture output rather than send to stdout and stderr.
>The technique is described in many places, for example
>https://www.blog.pythonlibrary.org/2016/06/16/python-101-redirecting-stdout/.
>Please be aware that due to the way Python3 changed its representation
>of strings (, unicode, bytes, etc.) you may have to be careful to find a
>solution that works portably.
>
>You could do this either in a Python wrapper script, or directly in the
>code you use to initialize your Python session (in C++).
>
>I'm only a casual Windows user (and even less programmer), so can't
>comment on any Windows-specific idioms to use.
>
>HTH,
> Stefan
>
>--
>
> ...ich hab' noch einen Koffer in Berlin...
>
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