During initialization, µC/OS-III creates a minimum of two (2) internal tasks (OS_IdleTask() and OS_TickTask()) and, three (3) optional tasks (OS_StatTask(), OS_TmrTask() and OS_IntQTask()). The optional tasks are created based on the value of compile-time #defines between 0 and 3 internal tasks depending on configuration constants found in os_cfg.h.:
OS_CFG_
...
TASK_
...
IDLE_EN enables OS_IdleTask()OS_CFG_
...
STAT_TASK_EN enables OS_StatTask()OS_CFG_
...
TMR_
...
EN enables OS_TmrTask()