Is it possible to check whether -e is set within a bash script?

Question

If a shell function needs a specific setting of -e/+e in order to work, is it possible to set that setting locally and then restore it to its previous setting before exiting the function?

myfunction()
{
   # Query here if -e is set and remember in a variable?
   # Or push the settings to then pop at the end of the function?
   set +e
   dosomething
   doanotherthing
   # Restore -e/+e as appropriate, don't just do unconditional   set -e
}

Answer 1

You have the flags currently set in the variable $-, so you can preserve this at the start of function and restore it after.

save=$-
...
if [[ $save =~ e ]]
then set -e
else set +e
fi

Answer 2

You can read the flag value thru the variable SHELLOPTS:

  > set +e 
  > echo $SHELLOPTS
    braceexpand:emacs:hashall:histexpand:history:interactive-comments:monitor
  > set -e 
  > echo $SHELLOPTS
    braceexpand:emacs:errexit:hashall:histexpand:history:interactive-comments:monitor

You see that, after setting set -e, the value errexit in $SHELLOPTS appears. You can check it from there.

However, you can get around this (if you wish!) by remembering the following point: according to the Manual:

-e:

..... This option applies to the shell environment and each subshell environment separately.

Thus, if you execute your function in a subshell, like

   zz="$(myfunction)"

you do not have to worry whether the errexit variable is set or not in calling environment, and you may set it as you like.