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determines the type of POST performed. Of course, it does not make sense to post LIFO and FIFO simultaneously, so these options are exclusive:
OS_OPT_POST_FIFO
POST message to task and place at the end of the queue if the task is not waiting for messages.
OS_OPT_POST_LIFO
POST message to task and place at the front of the queue if the task is not waiting for messages.
OS_OPT_POST_NO_SCHED
This option prevents calling the scheduler after the post and therefore the caller is resumed.
You should use this option if the task (or ISR) calling OSTaskQPost() will be doing additional posts, the user does not want to reschedule until all done, and multiple posts are to take effect simultaneously.
p_err
is a pointer to a variable that will contain an error code returned by this function.
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