How can I read a file from a C++ file launched in a Python subprocess?

Question

I'm trying to launch a C++ file using the python function "subprocess". I can begin the execution of the program, but it does not manage to read the data file I put in parameter.

However, when I lauch the C++ file directly with the same path to the same data the program works perfectly.

Do you have any ideas on why it does not work using a subprocess ?

The command line I'm using in my python file looks like this:

datafilePath="/home/*...*/dataFile.txt"

subprocess.run(["./programName", "-f "+datafilePath, (OtherOptionsWorkingFine) ],  cwd="./pathToMyProgram")
    

Answer 1

I think you are adding the datafilePath argument wrongly. Try to add all args as separate list items instead of concatenating (some of) them together as a string.

eg

subprocess.run(["./programName", "-f", datafilePath, (OtherOptionsWorkingFine) ],  cwd="./pathToMyProgram")