How to continue upon encountering nonexistent input files?

[Peng Yu]

$ awk -e '{ print }' x.txt <(builtin printf '%s\n' {1..3})awk: fatal:
cannot open file `x.txt' for reading: No such file or directory

As shown above, the above command stops when a nonexistent file is
encountered. Is there a way to let awk keep on proceeding (but allows
a way to handle the error in the awk code, e.g., print a customized
error message)?

-- 
Regards,
Peng