Master script calls helper scripts which calls C program, do not know how to get return value of C program

I have a master script that calls a helper script like so:

 bash -ex $SOME_DIR/

The helper script then calls a C program like so:

echo $?
.other functions called

The issue is that for starters I cannot get the return value from the C program.
The second issue is that nothing after my C program ends gets executed, the "other functions" do not get executed.

One important fact is the C program interacts with the serial ports and is printing things to the terminal. Once it is done talking to the external device it returns a value that I need to capture in my helper script to proceed.

However, if I call the helper script directly from terminal without use of the master script it works fine, I get the return value of the C program and the rest of the code executes.

I tried to reproduce the problem by writing a simple script that calls another which then calls a simple C program and I can reproduce.

I have some set +x here and there thinking this might be the issue but I do not believe so. I think perhaps the $? should be something else? But I am not well versed in Linux scripting. Some insight would be helpful.

Asked By: Eddiea6987


Since you run the helper script with bash -e, you will set the errexit shell option in the script. This shell option will cause the script to terminate if a simple command (like your C command) terminates with a non-zero exit status.

If you want to capture the exit status from your C program, either make sure not to use -e when starting the helper script or run the program as part of a AND/OR-list (which avoids terminating the script even if errexit is set and the program exits with a non-zero exit status):

./some_tester_in_C || status=$?

printf 'Exit status = %sn' "$status"
Answered By: Kusalananda
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