異步取消：被取消線程收到取消信號後，立即死亡。該線程縮持有的資源可能得不到釋放，這是一種非安全的線程取消方式。

延時取消：系統默認取消方式，是一種比較安全的線程取消機制，被取消線程取消時，只是設置取消點(ptcbDel->TCB_bCancelRequest)為true，被取消線程繼續運行，等到安全位置後進行取消操作。

取消點: 在使用延遲取消機制時，一個線程在可以被取消的地方定義取消點，當收到取消請求時，被取消的線程執行到取消點時退出，或者在一個取消點調用被阻塞時退出。

關鍵結構體
程序清單2.1 TCB結構體部分節選

typedef struct __lw_tcb {

...

??? LW_LIST_LINE????????? TCB_lineManage;????????? /? 內核管理用線表????????????? /

??? LW_LIST_RING????????? TCB_ringReady;?????????? /? 相同優先級就緒環??????????? /

???

??? LW_CLASS_WAKEUP_NODE? TCB_wunDelay;????? /? 等待節點??????????????????? /

#define TCB_ulDelay?????? TCB_wunDelay.WUN_ulCounter

...

#if (LW_CFG_EVENT_EN > 0) && (LW_CFG_MAX_EVENTS > 0)

??? LW_LIST_RING????????? TCB_ringEvent;????????? ???/? 事件等待隊列表????????????? /

??? PLW_CLASS_EVENT?????? TCB_peventPtr;??????????? /? 等待事件指針????????????? ?/

??? PLW_LIST_RING??????? TCB_ppringPriorityQueue;????? /? 在 PRIORITY 隊列位置???? */

??????????????????????????????????????????????? /? 由於刪除線程時需要解等待鏈，/

?????????????????????????????????????????????? /? 這時需要確定隊列位置??????? /

#endif

#if LW_CFG_COROUTINE_EN > 0

??? LW_CLASS_COROUTINE??? TCB_crcbOrigent;???????? /? 協程起源點????????????????? /

??? PLW_LIST_RING???????? TCB_pringCoroutineHeader;?? /? 協程首地址???????????????? /

#endif??????????????????????????????????????????? /? LW_CFG_COROUTINE_EN > 0???? /

...

??? volatile ULONG??????? TCB_ulCPUId;?????????? /? 如果正在運行, 表示運行 CPU? /

??? volatile BOOL???????? TCB_bIsCand;?????????? /? 是否在候選運行表中???????? ?/

#if LW_CFG_SMP_EN > 0

??? struct __lw_tcb????? TCB_ptcbWaitStatus;????????? /? 等待狀態修改的目標線程????? */

??? PLW_LIST_LINE???????? TCB_plineStatusReqHeader;???? /? 等待修改本線程狀態?????? /

??? LW_LIST_LINE????????? TCB_lineStatusPend;????????? /? 等待目標線程狀態修改?? ????/

#endif?????????????????????????????????????????????? /? LW_CFG_SMP_EN????????????? /

...

??? PLW_EVENTSETNODE????? TCB_pesnPtr;????? /? 指向該線程等待????????????? /

...

#if LW_CFG_THREAD_CANCEL_EN > 0

??? BOOL????????????????? TCB_bCancelRequest;???? /? 取消請求??????????????????? /

??? INT?????????????????? TCB_iCancelState;???????? /? 取消狀態??????????????????? /

??? INT?????????????????? TCB_iCancelType;????????? /? 取消類型??????????????????? /

#endif???????????????????????????????????????? /? LW_CFG_THREAD_CANCEL_EN???? /

...

#if LW_CFG_THREAD_DEL_EN > 0

??? struct __lw_tcb????? TCB_ptcbDeleteMe;?????? /? 要將本線程刪除的 TCB??????? */

??? struct __lw_tcb????? TCB_ptcbDeleteWait;???????? /? 等待對方刪除的 TCB????????? */

#endif???????????????????????????? ????????????????/? LW_CFG_THREAD_DEL_EN > 0??? /

??? UINT8???????????????? TCB_ucStackAutoAllocFlag;???? /? 堆棧是否有系統在堆中開辟?? /????????

??? PVOID???????????????? TCB_pvVProcessContext;?????? /? 進程上下文???????????????? /

...

} LW_CLASS_TCB;

程序清單2.2 等待隊列

typedef union {

??? PLW_LIST_RING???????? WL_pringFifo;????????????????? /? 基於先入先出的等待隊列?? /

??? PLW_LIST_RING???????? WL_pringPrio[__EVENT_Q_SIZE];? /? 基於優先級的等待隊列?? /

} LW_UNION_WAITLIST;

typedef LW_UNION_WAITLIST *PLW_UNION_WAITLIST;

typedef struct {

??? LW_UNION_WAITLIST???? WQ_wlQ;??????????????? /? 等待隊列??????????????????? /

??? UIN×××6??????????????? WQ_usNum;??????????????? /? 等待隊列中的線程個數??????? /

} LW_CLASS_WAITQUEUE;

typedef LW_CLASS_WAITQUEUE *PLW_CLASS_WAITQUEUE;

程序清單2.3 事件集

typedef struct {???????????????????????????????????????????? /? 事件集??????????????????? /

??? LW_LIST_MONO???????? EVENTSET_monoResrcList;???? /? 空閑資源表?????????????? /

??? UINT8??????????????? EVENTSET_ucType;????????????? /? 類型????????????????????? /

??? PLW_LIST_LINE??????? EVENTSET_plineWaitList;??????? /? 指向第一個等待線程??????? /

??? ULONG??????????????? EVENTSET_ulEventSets;???????? /? 32 bit 事件位???????????? /

??? ULONG??????????????? EVENTSET_ulOption;?????????? /? 事件集選項??????????????? /

??? UIN×××6?????????????? EVENTSET_usIndex;???????????? /? 數組中的索引????????????? /

??? CHAR???????????????? EVENTSET_cEventSetName[LW_CFG_OBJECT_NAME_SIZE];

???????????????????????????????????????????????????????? /? 事件標誌組名????????????? ?/

} LW_CLASS_EVENTSET;

typedef LW_CLASS_EVENTSET *PLW_CLASS_EVENTSET;

typedef struct {????????????????????????????????????????????? /? 事件集節點?????????????? /

??? LW_LIST_LINE???????? EVENTSETNODE_lineManage;???? /? 事件標誌組管理表??????? /

???

??? PVOID???????? ???????EVENTSETNODE_ptcbMe;?????? /? 指向等待任務的TCB??????? /

??? PVOID??????????????? EVENTSETNODE_pesEventSet;?? /? 指向標誌組??????????????? /

??? ULONG??????????????? EVENTSETNODE_ulEventSets;?? /? 標誌組開始等待?????????? /

??? UINT8??????????????? EVENTSETNODE_ucWaitType;???? /? 等待類型???????????????? /

} LW_CLASS_EVENTSETNODE;

typedef LW_CLASS_EVENTSETNODE?? *PLW_CLASS_EVENTSETNODE;

typedef PLW_CLASS_EVENTSETNODE?? PLW_EVENTSETNODE;

流程
API_ThreadCancel函數流程：

? ? ? 圖3.1 API_ThreadCancel函數

API_ThreadTestCancel函數流程：

圖3.2 API_ThreadTestCancel函數

pthread_delete函數流程：

圖3.3 pthread_delete函數

__threadDelete函數流程：

圖3.4 __threadDelete函數

SylixOS 線程取消處理流程