--- user/migration/v4_11-to-v5.rst | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)
diff --git a/user/migration/v4_11-to-v5.rst b/user/migration/v4_11-to-v5.rst index d42744d..8016a63 100644 --- a/user/migration/v4_11-to-v5.rst +++ b/user/migration/v4_11-to-v5.rst @@ -69,6 +69,23 @@ The directive :c:func:`rtems_clock_get` was removed. See section `Transition Advice for the Removed rtems_clock_get()` in the `RTEMS Classic API Guide` for alternatives. +File Descriptors +---------------- + +In RTEMS 5.1, the list of free file descriptors has a LIFO ordering in contrast +to previous versions where it was a FIFO. This means if an application +regularly opens and closes files (or sockets) it sees the whole range of file +descriptors. The reason for this change was to increase the time before file +descriptors are reused to more likely catch a file descriptor use after close. + +This change may surface application issues. If the configured file descriptor +maximum (``CONFIGURE_MAXIMUM_FILE_DESCRIPTORS``) is greater than the +``FD_SETSIZE`` defined by Newlib to 64, then calls to ``select()`` are undefined +behaviour and may corrupt the thread stack. It is possible to define a custom +``FD_SETSIZE``. The application must ensure that the custom ``FD_SETSIZE`` is +defined before ``<sys/select.h>`` is included in all modules used by the +application, for example via a global compiler command line define. + Networking ---------- -- 2.26.2 _______________________________________________ devel mailing list devel@rtems.org http://lists.rtems.org/mailman/listinfo/devel
