LFS201- Signals lab help

skaaa103

Just recently started the course and its my first time posting here so bare with me.

I'm working on the Section 4 Signals lab and I'm not entirely certain what to deduce based on the terminal output:

1. If more than one of a given signal is raised while the process has blocked it, does the process receive it multiple times? Does the behavior of real time signals differ from normal signals?
2. Are all signals received by the process, or are some handled before they reach it?
3. What order are the signals received in?

To that end:

Here's my output from Signals:

1. I don't know if the behavior of real time signals differs from normal signals and am looking for clarification on this
2. I can't tell if some or any of the signals are being handled before they reach the process. How would I determine that?

luisviveropena

Hi @skaaa103 ,

For answering item 1., you can see the man page for signal(7), subtitle "Real-time signals are distinguished by the following:".

Regards,
Luis.

coop

Please read the output, as it directly and clearly answers all the questions:

If more than one of a given signal is raised while the process has blocked it, does the process receive it multiple times? Does the behavior of real time signals differ from normal signals?

the next to last and last outputs show how many times they were received. Up to 32, only once, after that 3 times

Are all signals received by the process, or are some handled before they reach it?

You will notice some signals are not recorded, such as 9 and 19

What order are the signals received in?

once again the last output shows the order which is complicated until you get to the real time signals which are done in
ascending order, as the man page (I believe) explains.