下面的代碼摘自MSDN,對理解TLS很有幫助意義:
#include <stdio.h>
#include <windows.h>
#define THREADCOUNT 4
DWORD dwTlsIndex;
VOID ErrorExit(LPTSTR);
VOID CommonFunc(VOID)
{
LPVOID lpvData;
// Retrieve a data pointer for the current thread.
lpvData = TlsGetValue(dwTlsIndex);
if ((lpvData == 0) && (GetLastError() != 0))
ErrorExit("TlsGetValue error");
// Use the data stored for the current thread.
printf("common: thread %d: lpvData=%lx\n",
GetCurrentThreadId(), lpvData);
Sleep(5000);
}
DWORD WINAPI ThreadFunc(VOID)
{
LPVOID lpvData;
// Initialize the TLS index for this thread.
lpvData = (LPVOID) LocalAlloc(LPTR, 256);
if (! TlsSetValue(dwTlsIndex, lpvData))
ErrorExit("TlsSetValue error");
printf("thread %d: lpvData=%lx\n", GetCurrentThreadId(), lpvData);
CommonFunc();
// Release the dynamic memory before the thread returns.
lpvData = TlsGetValue(dwTlsIndex);
if (lpvData != 0)
LocalFree((HLOCAL) lpvData);
return 0;
}
DWORD main(VOID)
{
DWORD IDThread;
HANDLE hThread[THREADCOUNT];
int i;
// Allocate a TLS index.
if ((dwTlsIndex = TlsAlloc()) == 0xFFFFFFFF)
ErrorExit("TlsAlloc failed");
// Create multiple threads.
for (i = 0; i < THREADCOUNT; i++)
{
hThread[i] = CreateThread(NULL, // no security attributes
0, // use default stack size
(LPTHREAD_START_ROUTINE) ThreadFunc, // thread function
NULL, // no thread function argument
0, // use default creation flags
&IDThread); // returns thread identifier
// Check the return value for success.
if (hThread[i] == NULL)
ErrorExit("CreateThread error\n");
}
for (i = 0; i < THREADCOUNT; i++)
WaitForSingleObject(hThread[i], INFINITE);
return 0;
}
VOID ErrorExit (LPTSTR lpszMessage)
{
fprintf(stderr, "%s\n", lpszMessage);
ExitProcess(0);
}
輸出:thread 968: lpvData=143010
common: thread 968: lpvData=143010
thread 184: lpvData=143118
common: thread 184: lpvData=143118
thread 828: lpvData=143220
common: thread 828: lpvData=143220
thread 268: lpvData=143328
common: thread 268: lpvData=143328
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