> For some handle types like sockets, for hardware reasons (multicore CPUs) Linux no longer guarantees sequential file descriptors.
huh? this would be a severe POSIX violation, which says that for socket and accept, "The file descriptor shall be allocated as described in File Descriptor Allocation.": "All functions that open one or more file descriptors shall, unless specified otherwise, atomically allocate the lowest numbered available (that is, not already open in the calling process) file descriptor at the time of each allocation."
huh? this would be a severe POSIX violation, which says that for socket and accept, "The file descriptor shall be allocated as described in File Descriptor Allocation.": "All functions that open one or more file descriptors shall, unless specified otherwise, atomically allocate the lowest numbered available (that is, not already open in the calling process) file descriptor at the time of each allocation."