I'm not sure if it's required (to know the exit code). inputs, both valid and invalid, will activate various paths in djpeg/libjpeg, and that's the basic goal here.

In case you'd like to test persistent fuzzing (should be faster due to a few factors), you can try modifying https://github.com/google/honggfuzz/blob/master/examples/lib... - it will probably take creating main() func which will read data in the AFL_LOOP() loop and call LLVMFuzzerTestOneInput with that input.