Getting the rom name and emulator

daveyman123

@meleu
there is still the problem of (i dont know if i mentioned it) the unicorn only scrolls through ONCE (even if i include a loop in python) then it will play a random sequence of lights. I.E. it reads "JIM" or "GOLDEN" in "GOLDENEYE". But as soon as the game launches it freezes or plays random lights.

My fear is it has something to do with the pins being messed with by retropie. I have not tried to replicate the problem on raspbian.. but I may have to try that.

What I have tried:
making sure audio isnt interfering with the unicorn hat pins (i.e. setting the audio output to hdmi)
and obviously have tried making the python script run in the background

Sano

@meleu said in Getting the rom name and emulator:

sudo /path/to/python/code.py "$rom_name" &

Try to modify this line like this :

sudo nohup /path/to/python/code.py "$rom_name" &

daveyman123

@Sano
nohup was nohelp... lol

something is happening at the level of the pins i believe

Sano

Ok sorry, could you try

nohup sudo /path/to/python/code.py "$rom_name" &

(possibly with quotes)
I'm pretty sure it's because the parent process (runcommand-onstart) terminates before game launch, so the child are killed, including your script.
This could be solved with the use of nohup, if I ever remember the correct syntax with sudo...

daveyman123

@sano

does nothing when i do that

my hunch is it has to do with the support for GPIO controllers in retropie. I could be wrong

daveyman123

nah thats not it. The driver packages for GPIO controllers isnt installed

daveyman123

I got it to work with a different game "super mario for snes" so... the problem must be in the emulator settings

daveyman123

I think ive pretty much figured it out boys thanks to your help

first one to link their paypal gets 20 dollars when freelancer clears

meleu

@sano said in Getting the rom name and emulator:

I'm pretty sure it's because the parent process (runcommand-onstart) terminates before game launch, so the child are killed

I'm afraid this isn't true. Once a process is forked it doesn't depends on his parent life (oh these childrens of today...).

I didn't test with the actual -onstart script, but tested a similar scenario in command line before posting.

meleu

@daveyman123 said in Getting the rom name and emulator:

first one to link their paypal gets 20 dollars when freelancer clears

If you click on my name at right of my avatar you can see it on my profile page. ;-)

daveyman123

will do!

meleu

@sano Here is a way to prove what I said:

[PROMPT]$ cat father.sh
#!/bin/bash
echo "FATHER: Hello, I am the father."
echo "FATHER: Hey son, say hello to the world!"
bash son.sh &
sleep 10
echo "FATHER: Oh no! I am going to die! NOOOOOoooooo..."
sleep 1
echo "FATHER: bye!"
exit

[PROMPT]$ cat son.sh
#!/bin/bash
while true; do
    echo "SON: Hello World!"
    sleep 2
done

[PROMPT]$ bash father.sh
FATHER: Hello, I am the father.
FATHER: Hey son, say hello to the world!
SON: Hello World!
SON: Hello World!
SON: Hello World!
SON: Hello World!
SON: Hello World!
FATHER: Oh no! I am going to die! NOOOOOoooooo...
SON: Hello World!
FATHER: bye!

[PROMPT]$ SON: Hello World!
SON: Hello World!
SON: Hello World!
SON: Hello World!
SON: Hello World!
SON: Hello World!
SON: Hello World!
SON: Hello World!
...

cyperghost

@meleu I made same intention here
Every 5 seconds one entry is written in log file for 10 times. After a minute or of intensive gaming (Joust Arcade!) you can check tmp/counter.log voila... entry of used Arcade system is there 10 times :)

Sano

@meleu @cyperghost
My bad then, you're right of course ;)

Edit : my guess would only be valid (I think) if the user launching the script disconnects afterward, which is not the case here.
I was probably misled by the statement that the scrolling stops when the game launch.
It was late here anyway, I was drunk, and my cat was distracting me.
Well, enough justifications I think. I'm just obviously no good at this :)

cyperghost

@sano The father & son example of @meleu is very reasonable.
High laughter for this :)

Where is grandma-bash? Will son-bash be father soon?

meleu

@cyperghost @Sano
One more note: the init process (the famous "PID 1") is the orphanage. When a parent process dies, its orphan children are "adopted" by init.

Play a little with that father & son example and check the process table with the ps -alf. Look at the PPID column of the son.shprocess before and after the father.sh's death. ;)

cyperghost

@meleu I see, so the PID changes after the father is dead. So it's necessary to check PID during run if I want to elemenate son.sh
That's indeed interesting and I hopefully will remember if I'm in need to kill everlasting bash process!

meleu

@cyperghost said in Getting the rom name and emulator:

@meleu I see, so the PID changes after the father is dead. So it's necessary to check PID during run if I want to elemenate son.sh

No, no! What changes is the PPID (Parent's PID)! The PID never changes!

cyperghost

@meleu Thank you for clearance. But is the PPID in any way important or is there a usecase? (maybe dumb question?)

EDIT:
Answered myself. The PPID gives relationship of calls so you always know which programm started process x or process y. Helpfull indeed!

meleu

@cyperghost it's not a dumb question at all :)

You can commit a genocide with a Parent's PID.

If a father's PID is 123, you can kill it and all its descendants with

kill -9 -123

But you wouldn't do such villainy, would you?