use of global

[wpo]

Thx for the very quick reply. I had read that information already before, and I think that my "test" scripts are in line with what is recommended there. Still, it does not function as intended.
I have attached here my two scripts (the main script that is ran, and the imported script with the functions:

# this is file "testglobalsextmain.py"

from testglobalsextimport import *

global a,b,c

a = "a"
b = "b"
c = "c"
x = "?"

print ("main ",a,b,c,x)
    
d=f1(a)
d=f2(a)
b = "b2"
d=f2(a)

print ("end  ",a,b,c,x)

#and

# this is file "testglobalsextimport.py"

def f1(x):
    global a,b,c
    b = "f1b"
    c = "f1c"
    print ("f1   ",a,b,c,x)
    
def f2(x):
    global a,b,c
    print ("f2   ",a,b,c,x)

When I run the "main" script, I get this output:

Output:
>>> 
 RESTART: G:\UserData\Willy\Documents\Willys_Programmas\Test_routines\testglobalsextmain.py 
main  a b c ?
Traceback (most recent call last):
  File "G:\UserData\Willy\Documents\Willys_Programmas\Test_routines\testglobalsextmain.py", line 14, in <module>
    d=f1(a)
  File "G:\UserData\Willy\Documents\Willys_Programmas\Test_routines\testglobalsextimport.py", line 7, in f1
    print ("f1   ",a,b,c,x)
NameError: name 'a' is not defined
>>> 

Can anybody please tell me what I did wrong?