Comtrol eCos - Manual (Page 478)

Chapter 32. µITRON API
T_MSG **ppk_msg, ID mbxid )
ER trcv_msg (
T_MSG **ppk_msg, ID mbxid , TMO tmout )
ER ref_mbx (
T_RMBX *pk_rmbx, ID mbxid )
The following functions are supported in this release (with some restrictions) if enabled with the appropriate con-
figuration option for the object type (for example
CYGPKG_UITRON_SEMAS_CREATE_DELETE ):
ER cre_sem (
ID semid, T_CSEM *pk_csem )
ER del_sem (
ID semid )
ER cre_flg (
ID flgid, T_CFLG *pk_cflg )
ER del_flg (
ID flgid )
ER cre_mbx (
ID mbxid, T_CMBX *pk_cmbx )
ER del_mbx (
ID mbxid )
In general the queueing order when waiting on a synchronization object depends on the underlying kernel config-
uration. The multi-level queue scheduler is required for strict µITRON conformance and it queues tasks in FIFO
order, so requests to create an object with priority queueing of tasks (
pk_cxxx- > xxxatr = TA_TPRI ) are rejected
with E_RSATR. Additional undefined bits in the attributes fields must be zero.
In general, extended information (pk_cxxx->exinf) is ignored.
For semaphores, the initial semaphore count (pk_csem->isemcnt) is supported; the new semaphore’s count is set.
The maximum count is not supported, and is not in fact defined in type pk_csem.
For flags, multiple tasks are allowed to wait. Because single task waiting is a subset of this, the W bit (TA_WMUL)
of the flag attributes is ignored; all other bits must be zero. The initial flag value is supported.
For mailboxes, the buffer count is defined statically by kernel configuration option
CYGNUM_KERNEL_SYNCH_MBOX_QUEUE_SIZE ; therefore the buffer count field is not supported and is not in fact
defined in type pk_cmbx. Queueing of messages is FIFO ordered only, so TA_MPRI (in pk_cmbx->mbxatr) is
not supported.
Error checking
The following conditions are only checked for, and only return errors if
CYGSEM_UITRON_BAD_PARAMS_RETURN_ERRORS is enabled:
• invalid object id; less than 1 or greater than CYGNUM_UITRON_TASKS/SEMAS/MBOXES as appropriate returns
E_ID
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