[Concurrent parallel]_[c/c++]_[uses thread-local storage for threads locally Storage (TLS)-win32 and pthread comparison]

Scene:

1. You need to count the number of objects created on a thread.

2. When the heap space is created, it needs to be destroyed based on the thread needs to be created and ended.

3. Because the scope is that a thread can only see its own stored data, it does not require a critical section or mutex to maintain its own heap memory. Join if implemented with global STD::MAP, you must lock on put and get, which is a waste of resources.

4. Can be used to maintain a connection, such as a socket,database connection.

Description

1. Java also has its own thread-local storage threadlocal

2. Win32 version of Pthread: http://sourceware.org/pthreads-win32/

Example Test_tsl.cpp:

#include "stdafx.h" #include <stdio.h> #include <stdint.h> #include <stdlib.h> #include <assert.h > #include <windows.h> #include "pthread.h" #define THREADCOUNT 4 DWORD dwtlsindex; VOID errorexit (const char*); static pthread_barrier_t barrier = null;static pthread_once_t random_is_initialized = pthread_once_init;static Pthread_ key_t key;  void Commonfunc (void) {LPVOID lpvdata;     Retrieve a data pointer for the current thread.    Lpvdata = TlsGetValue (Dwtlsindex);  if ((Lpvdata = = 0) && (GetLastError ()! = ERROR_SUCCESS)) errorexit ("TlsGetValue ERROR");    Use the data stored to the current thread.   int64_t* value = (int64_t*) lpvdata;     printf ("Common:thread%d:lpvdata=%lx:value=%lld\n", GetCurrentThreadID (), lpvdata,*value); Sleep (5000);  } DWORD WINAPI ThreadFunc (VOID) {lpvoid lpvdata;     Initialize the TLS index for this thread.    Lpvdata = (LPVOID) LocalAlloc (LPTR, 8); if (!  TlsSetValue (Dwtlsindex, Lpvdata))     Errorexit ("TlsSetValue error");   int64_t* value = (int64_t*) lpvdata;   *value = GetCurrentThreadID ();     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;    }void Testwin32tls () {DWORD idthread;    HANDLE Hthread[threadcount];  int i;     Allocate a TLS index.   if (Dwtlsindex = TlsAlloc ()) = = tls_out_of_indexes) errorexit ("TlsAlloc failed"); 1.   Note that this dwtlsindex is not starting from 0.     printf ("Dwtlsindex%ld\n", dwtlsindex);//Create multiple threads.                            for (i = 0; i < ThreadCount; i++) {Hthread[i] = CreateThread (NULL,//default 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); TlsFree (Dwtlsindex);}   void Commonfuncpthread (void) {void* lpvdata = pthread_getspecific (key);   int64_t* value = (int64_t*) lpvdata; printf ("Common:thread%d:lpvdata=%lx:value=%lld\n", GetCurrentThreadID (), lpvdata,*value); }void* startpthread (void* data) {int64_t *buf = (int64_t*) malloc; *buf = GetCurrentThreadID ();p thread_setspecific ( Key, BUF);    Commonfuncpthread (); free (BUF); Pthread_barrier_wait (&barrier); return NULL;} 1. Call only once, can be placed at random a work thread execution function can, will randomly find a thread execution.//2. Dll_process_attach similar to Win32 is performed only once. void Testpthreadtls () { Pthread_key_create (&key, NULL);p thread_barrier_init (&barrier,null, ThreadCount + 1); for (int i = 0; i< ThreadcounT ++i) {pthread_t t;pthread_create (&t,null,startpthread,null);p Thread_detach (t);} 1. Wait for other threads to finish executing. pthread_barrier_wait (&barrier);p thread_key_delete (key);}   DWORD Main (VOID) {//1.win32tls printf ("testwin32tls\n");   Testwin32tls ();   1.pthread TLS printf ("testpthreadtls\n");   Testpthreadtls (); return 0;    } VOID errorexit (const char* lpszmessage) {fprintf (stderr, "%s\n", lpszmessage); ExitProcess (0); }

.

Output:

Testwin32tlsdwtlsindex 26thread 8452:lpvdata=714f50common:thread 8452:lpvdata=714f50:value=8452thread 8460:lpvdata =7153d0common:thread 8460:lpvdata=7153d0:value=8460thread 8456:lpvdata=715610common:thread 8456:lpvdata=715610:va Lue=8456thread 8464:lpvdata=715190common:thread 8464:lpvdata=715190:value=8464testpthreadtlscommon:thread 8520: Lpvdata=3b4eb0:value=8520common:thread 8512:lpvdata=3b4ff0:value=8512common:thread 8516:lpvdata=3b4eb0:value=851 6common:thread 8524:lpvdata=3b4ff0:value=8524

Reference:

https://msdn.microsoft.com/en-us/library/windows/desktop/ms686749 (v=vs.85). aspx

https://msdn.microsoft.com/en-us/library/windows/desktop/ms686991 (v=vs.85). aspx

Http://blog.chinaunix.net/uid-10231348-id-3034751.html

http://blog.csdn.net/liulina603/article/details/17991731

Http://linux.die.net/man/3/pthread_once

[Concurrent parallel]_[c/c++]_[uses thread-local storage for threads locally Storage (TLS)-win32 and pthread comparison]