Replace all calls to sigqueue() in the OS proper with calls to nxsig_queue() to avoid accessing the errno variable.
sched/signal: Add nxsig_queue() which is functionally equivalent to sigqueue() except that it does not modify the errno variable.
This commit backs out most of commit b4747286b1. That change was added because sem_wait() would sometimes cause cancellation points inappropriated. But with these recent changes, nxsem_wait() is used instead and it is not a cancellation point.
In the OS, all calls to sem_wait() changed to nxsem_wait(). nxsem_wait() does not return errors via errno so each place where nxsem_wait() is now called must not examine the errno variable.
In all OS functions (not libraries), change sem_wait() to nxsem_wait(). This will prevent the OS from creating bogus cancellation points and from modifying the per-task errno variable.
sched/semaphore: Add the function nxsem_wait(). This is a new internal OS interface. It is functionally equivalent to sem_wait() except that (1) it is not a cancellation point, and (2) it does not set the per-thread errno value on return.
sched/semaphore: Add nxsem_post() which is identical to sem_post() except that it never modifies the errno variable. Changed all references to sem_post in the OS to nxsem_post().
sched/semaphore: Add nxsem_destroy() which is identical to sem_destroy() except that it never modifies the errno variable. Changed all references to sem_destroy() in the OS to nxsem_destroy().
libc/semaphore and sched/semaphore: Add nxsem_getprotocol() and nxsem_setprotocola which are identical to sem_getprotocol() and set_setprotocol() except that they never modifies the errno variable. Changed all references to sem_setprotocol in the OS to nxsem_setprotocol(). sem_getprotocol() was not used in the OS
libc/semaphore: Add nxsem_getvalue() which is identical to sem_getvalue() except that it never modifies the errno variable. Changed all references to sem_getvalue in the OS to nxsem_getvalue().
sched/semaphore: Rename all internal private functions from sem_xyz to nxsem_xyz. The sem_ prefix is (will be) reserved only for the application semaphore interfaces.
libc/semaphore: Add nxsem_init() which is identical to sem_init() except that it never modifies the errno variable. Changed all references to sem_init in the OS to nxsem_init().
sched/semaphore: Rename sem_tickwait() to nxsem_tickwait() so that it is clear this is an internal OS function.
sched/semaphoate: Rename sem_reset() to nxsem_reset() so that it is clear this is an internal OS function.
drivers/xbee: Fixes a few warnings
* drivers/xbee: Fixes a few warnings
* configs/clicker2-stm32: Updates sections about i8sak usage in the README
Approved-by: Gregory Nutt <gnutt@nuttx.org>
drivers/wireless: Adds XBee S2C (802.15.4 firmware) support. XBee driver emulates mac802154 interface
* drivers/wireless/xbee: Adds xbee_netdev. Very similar to mac802154_netdev
* configs/same70-xplained: Starts adding support for XBee radio
* drivers/wireless/ieee802154/xbee: More structuring of XBee driver
* drivers/wireless/ieee802154/xbee: More Xbee work. Starts adding support on Clicker2
* drivers/wireless/ieee802154/xbee: More XBee MAC code
* configs/clicker2-stm32: More work to add XBee radio support
* drivers/wireless/ieee802154/xbee: Most of driver is now structured. No build errors
* configs/clicker2-stm32: Adjustments to XBee click module support
* drivers/xbee: Changes md_ prefix to xd_ prefix for xbeenet_driver_s fields
* drivers/xbee: XBee network device now passes MAC events via IOCTL
* drivers/xbee: Support querying device for parameters, setting parameters, and structures association/startpan logic
* configs/clicker2-stm32: Fixes Xbee lower half ATTN poll logic
* drivers/xbee: Removes dependce on CONFIG_IEEE802154_NETDEV
* drivers/xbee: Supports MAC RESET.request primitive
* drivers/xbee: Exposes generic AT query to the rest of driver
* drivers/xbee: Sets local values when writing setting change to Xbee device
* drivers/xbee: Finish association logic
* drivers/xbee: Adds xbee_get_mhrlen( ) allocating enough space for API frame header to frame
* drivers/xbee: Finishes transmit/receive logic
* drivers/xbee: Fixes xbee_netdev to match logic in mac802154_netdev.c
* drivers/xbee: Rearranges logic to prevent a loop condition where recursion could potentially occur to the point of deadlocking the system
Approved-by: Gregory Nutt <gnutt@nuttx.org>
