Hi, Recently, we saw one customer hitting an error during file I/O with error "Unknown error" 524. Since this error does not translate to any error using strerror(), it was quite confusing. Only when I saw that in errno.h in Linux kernel, I could see that this error corresponds to ENOTSUPP, which we return in a few places in our code. I also noticed that there's an error ENOTSUP, which does translate to a userspace error. My question here are: 1. What's the purpose of these two error codes which look similar? 2. Who should we talk to about having corresponding translation in strerror? 3. Should we be returning ENOTSUPP to userspace at all? The open man page says that for ENOTSUPP: The filesystem containing pathname does not support O_TMPFILE. Is this the only reason where we return ENOTSUPP? -- -Shyam
