Yes: EPERM mode requested creation of something other than a regular file, FIFO (named pipe), or UNIX domain socket, and the caller

Yes: EPERM mode requested creation of something other than a regular file, FIFO (named pipe), or UNIX domain socket, and the caller is not privileged (Linux: does not have the CAP_MKNOD capability); also returned if the filesystem containing pathname does not support the type of node requested. Of course there is still the theoretical problem that you could be running in a chroot where some unprivileged user has write access to the root and/or /dev so that she can create symlinks or move files around there. I don't think that should be the responsibility of the library to defend against though; but the responsibility of whoever created that chroot dir...