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is a pointer to a variable that is used to hold an error code:
OS_ERR_NONE
if If the call is successful and the mutex has been deleted.
OS_ERR_DEL_ISR
if If OS_CFG_CALLED_FROM_ISR_CHK_EN set to 1 in os_cfg.h: if attempting to delete a mutex from an ISR.
OS_ERR_OBJ_PTR_NULL
if If OS_CFG_ARG_CHK_EN is set to 1 in os_cfg.h: if p_mutex is a NULL pointer.
OS_ERR_OBJ_TYPE
if If OS_CFG_OBJ_TYPE_CHK_EN is set to 1 in os_cfg.h: if p_mutex is not pointing to a mutex.
OS_ERR_OPT_INVALID
if If the user does not specify one of the two options mentioned in the opt argument.
OS_ERR_TASK_WAITING
if If one or more task are waiting on the mutex and OS_OPT_DEL_NO_PEND is specified.
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