Making CPP exe prints into Python script input

Question

I have a Python script I want to get information from a CPP .exe I have.

The .exe prints a string to console using printf.

I want to be able to get this string into my Python code.

I want to be able, in my Python code, to do something like this :

gyro_data = GetFromCommandLine(cpp.exe.run())

Also - my cpp.exe has a loop that runs forever and keeps feeding console with strings. Can this be done? Or do I have to break my cpp exe to return something instead of printing to screen all the time ?

• Ofri: I will edit my question

Answer 1

I would suggest using the subprocess module.

You will then be able to do something like (this code is from their documentation, which requires Python 3.7)

subprocess.run(["ls", "-l", "/dev/null"], capture_output=True)

which returns

CompletedProcess(args=['ls', '-l', '/dev/null'], returncode=0,
stdout=b'crw-rw-rw- 1 root root 1, 3 Jan 23 16:23 /dev/null\n', stderr=b'')

For earlier versions, you would use subprocess.Popen like this

your_process = Popen(['ls', '-l', '/dev/null'], stdout=subprocess.PIPE)
your_process.wait()
your_process_output = your_process.stdout().decode() # Here you will have a string

This snippet could very easily be wrapped into a single function.

• Ofri: I will test it :)
• Ofri: So if my exe is constantly printing a string, example: quat 1.1 2.5 1.4 6.5 over and over again, the code you wrote will run for every entry ? or can I run it a single time for one entry ?
• Ofri: Also, I now get an exception "file object is not callable"