check if trace32 has finished initialising when launched with python

i have seen the below code in the python trace32 demos where the functin subprocess.Popen is used to launch trace32 using python.

# Launch TRACE32 as a sub process - this prevents our script
# from blocking
t32process=subprocess.Popen([T32BIN,'-c',CONFIGFILE])
# Wait a few seconds to give TRACE32 time to initialise - this may
# be up to 8 seconds depending upon the hardware and connection
# method. For SIM, we'll use 3 seconds.
time.sleep(3)

In this case the time to wait for the initialisation was 3 seconds. However this varies and so my question is, is there a way to programmatically check if TRACE32 has finished initialising ?

The command line flag -s <startup_script> [<args>] [1] allows you to define a TRACE32 script file that is automatically executed once the initialization phase has completed. This script could then set a signal to indicate the completion of the initialization, e.g.

1. t32process=subprocess.Popen([T32BIN,'-c',CONFIGFILE, '-s', '<startup_script>', '<token>']) starts TRACE32 with a unique token for the startup script.
2. The TRACE32 script uses the token to create a file.
3. The Python code polls for the existence of the file and waits until the file is available.

A simple startup script start.cmm could look like this

PRIVATE &token

ENTRY &token

OPEN #1 t32."&token" /Create
CLOSE #1

Starting TRACE32 with the command

t32marm.exe -c config.t32 -s start.cmm "12345"

would create the file t32.12345 in the current working directory.