Saving return value of subprocess.Popen to a global variable

Question

Is it possible to save or store the return value of a subprocess.Popen() to a global variable? For example,

global_var = none
 ...
 def some_function():
    p = subprocess.Popen(...,stdout=subprocess.PIPE, shell=True)
    global_var = p

 def some_function_2():
    x = global_var.stdout

Something like this. I'm essentially trying to read output from a subprocess that is started earlier in code but I need to begin the read later on.

Answer 1

So this ended up being a silly oversight. All I needed to do was call global and the global variable name inside the function to set its value correctly like so:

global_var = none
 ...
 def some_function():
    p = subprocess.Popen(...,stdout=subprocess.PIPE, shell=True)
    global global_var
    global_var = p

 def some_function_2():
    x = global_var.stdout

Answer 2

You need to add one line to some_function . I also give a better solution.

 global_var = None  
 ...
 def some_function():
    global global_var # without this line, Python will create a local named global_variable
    p = subprocess.Popen(...,stdout=subprocess.PIPE, shell=True)
    global_var = p

 def some_function_2():
    x = global_var.stdout

Better is:

 def some_function():
    # I assume this function does some other things, otherwise
    # you don't need to write a function to just call another.
    p = subprocess.Popen(...,stdout=subprocess.PIPE, shell=
    return p

 my_process = some_function()

 def some_function_2():
    x = my_process.stdout