This appears to be regularly confused with EACCES. To quote from SUSv3:
In general, EACCES seems more to be used for file permission conflicts, while EPERM seems more likely to be used for process-related permission conflicts. But you can see that even system calls use them differently.
actually, EACCES for permissions based things (different owners, file permissions, etc) while EPERM covers things where you are trying to break the rules.
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