使用信標對象實現線程同步
使用信標對象實現線程同步
信標對象也屬於系統內核對象之一,它包含有計數,當使用計數爲0時,信標對象處於無信號狀態;
當使用計數大於0時,信標計數處於有信號狀態。
相關函數:
CreateSemaphore:用於創建一個信標對象
HANDLE CreateSemaphore(LPSECURITY_ATTRIBUTES lpSemaphoreAttributes,LONG lInitialCount,LONG lMaxinumCount,LPCTSTR lpName);
lpSemaphoreAttributes:表示安全屬性,可以是NULL
lInitialCount:初始計數
lMaxinumCount:最大計數
lpName:信標名稱
ReleaseSemaphore:用於遞增信號量的使用計數
BOOL ReleaseSemaphore(HANDLE hSemphore,LONG lReleaseCount,LPLONG lpPreviousCount)
hSemphore:句柄
lReleaseCount信標的遞增數量
lpPreviousCount:用於返回之前的信標的使用計數
示例:
UINT output11(LPVOID pThreadParam)
{
CString text;
CAccessConflictDlg *pdlg=(CAccessConflictDlg *)pThreadParam;
long nCount=0;
while(pdlg->m_count<=100)
{
WaitForSingleObject(pdlg->m_semaphore,INFINITE);//等待信標對象有信號
text.Format("線程一輸出%d",pdlg->m_count);
pdlg->m_count++;
pdlg->m_list.AddString(text);
Sleep(100);
ReleaseSemaphore(pdlg->m_semaphore,1,&nCount);
}
return 0;
}
UINT output22(LPVOID pThreadParam)
{
CString text;
CAccessConflictDlg *pdlg=(CAccessConflictDlg *)pThreadParam;
long nCount=0;
while(pdlg->m_count<=100)
{
WaitForSingleObject(pdlg->m_semaphore,INFINITE);//等待信標對象有信號
text.Format("線程二輸出%d",pdlg->m_count);
pdlg->m_count++;
pdlg->m_list.AddString(text);
Sleep(100);
ReleaseSemaphore(pdlg->m_semaphore,1,&nCount);
}
return 0;
}
void CAccessConflictDlg::OnButton1()
{
m_semaphore=CreateSemaphore(NULL,1,100,"sem");
output1=AfxBeginThread(output11,this,0,0,0,NULL);
output2=AfxBeginThread(output22,this,0,0,0,NULL);
CloseHandle(output1->m_hThread);
CloseHandle(output2->m_hThread);
// TODO: Add your control notification handler code here
}
信標對象也屬於系統內核對象之一,它包含有計數,當使用計數爲0時,信標對象處於無信號狀態;
當使用計數大於0時,信標計數處於有信號狀態。
相關函數:
CreateSemaphore:用於創建一個信標對象
HANDLE CreateSemaphore(LPSECURITY_ATTRIBUTES lpSemaphoreAttributes,LONG lInitialCount,LONG lMaxinumCount,LPCTSTR lpName);
lpSemaphoreAttributes:表示安全屬性,可以是NULL
lInitialCount:初始計數
lMaxinumCount:最大計數
lpName:信標名稱
ReleaseSemaphore:用於遞增信號量的使用計數
BOOL ReleaseSemaphore(HANDLE hSemphore,LONG lReleaseCount,LPLONG lpPreviousCount)
hSemphore:句柄
lReleaseCount信標的遞增數量
lpPreviousCount:用於返回之前的信標的使用計數
示例:
UINT output11(LPVOID pThreadParam)
{
CString text;
CAccessConflictDlg *pdlg=(CAccessConflictDlg *)pThreadParam;
long nCount=0;
while(pdlg->m_count<=100)
{
WaitForSingleObject(pdlg->m_semaphore,INFINITE);//等待信標對象有信號
text.Format("線程一輸出%d",pdlg->m_count);
pdlg->m_count++;
pdlg->m_list.AddString(text);
Sleep(100);
ReleaseSemaphore(pdlg->m_semaphore,1,&nCount);
}
return 0;
}
UINT output22(LPVOID pThreadParam)
{
CString text;
CAccessConflictDlg *pdlg=(CAccessConflictDlg *)pThreadParam;
long nCount=0;
while(pdlg->m_count<=100)
{
WaitForSingleObject(pdlg->m_semaphore,INFINITE);//等待信標對象有信號
text.Format("線程二輸出%d",pdlg->m_count);
pdlg->m_count++;
pdlg->m_list.AddString(text);
Sleep(100);
ReleaseSemaphore(pdlg->m_semaphore,1,&nCount);
}
return 0;
}
void CAccessConflictDlg::OnButton1()
{
m_semaphore=CreateSemaphore(NULL,1,100,"sem");
output1=AfxBeginThread(output11,this,0,0,0,NULL);
output2=AfxBeginThread(output22,this,0,0,0,NULL);
CloseHandle(output1->m_hThread);
CloseHandle(output2->m_hThread);
// TODO: Add your control notification handler code here
}
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