You can only say one thing about a return code of 1 ... it is not 0.

Zero is conventionally "success" ... it means "there was no error to be reported" ... hence, zero.

Everything else is treated as Not 0 ... it could mean failure, it could mean a warning, it could mean success. It is up to the person(s) who wrote the code you are running. This is why i think it is vital to capture STDERR as well.

L-LL-L--L-LL-L--L-LL-L--
-R--R-RR-R--R-RR-R--R-RR
B--B--B--B--B--B--B--B--
H---H---H---H---H---H---
(the triplet paradiddle with high-hat)