Merge branch 'main' of github.com:PP189B/Multithreaded-programming-practice into main

Author: mgroot

5_Processes_Signals_Files_Pipes/README.md

@@ -4,14 +4,16 @@
 Some simple tasks from the course + additional practice with my own examples:
 |||
 |-------------------|-----------------------------------------------------------|
-|1. `Processes/exec_cat.cpp`  | Just execute cat in forked proccess with error checks |
+|1. `Processes/1_exec-cat.cpp`        | Just execute cat in forked proccess with error checks |
+|2. `Processes/2_Zombie-checker.cpp`  | Checking zombie child processes in non-blocking mode  |
+|2. `Signals/1_Immortal.cpp`          | Just making immortal (ignoring `SIGINT` and `SIGTERM`) child process |
 
 
 
 
 ## Result
 
-### `Processes/exec_cat.cpp`
+### `Processes/1_exec-cat.cpp`
 
 Simple exec in forked process (after 1 sec sleep) with reusing argv parameters with.
 
@@ -20,7 +22,27 @@ Simple exec in forked process (after 1 sec sleep) with reusing argv parameters w
 ![Screen Recording 2022-03-17 at 12 09 31 PM](https://user-images.githubusercontent.com/44144647/158776572-3c0f3b56-28a8-492b-af01-83faa5a3a80b.gif)
 
 
+### `Processes/2_Zombie-checker.cpp`
 
+Fork `CHILDS_NUMBER` processes (with 1 seconds delay between) and make them sleep for `5 + std::rand() % 20` seconds (each process has own random seed).
 
-## Learned new
+After fork main process doing `some hard work` and each `WORK_DELAY` seconds calls `zombie_check()` in non-blocking mode.
+
+##### runtime
+
+![Screen Recording 2022-03-17 at 1 52 17 PM](https://user-images.githubusercontent.com/44144647/158794971-b93aeb31-de99-4868-b71f-34829766ef27.gif)
+
+
+### `Signals/1_Immortal.cpp`
+
+Just making immortal (ignoring `SIGINT` and `SIGTERM`) child process.
 
+##### runtime
+
+![Screen Recording 2022-03-17 at 12 29 11 PM](https://user-images.githubusercontent.com/44144647/158795441-6ad4b09a-ec8f-40c1-8f65-493f366bc1bf.gif)
+
+
+
+## Learned new
+* Non-blocking `waitpid`'s flag (`WNOHANG`)
+* ANSI, POSIX and Real Time signals