多线程

#include "toolbox.h"
#include <utility.h>
#include <cvirte.h>  
#include <userint.h>
#include "multi thread.h"

//传递所创建线程的callbackData参数
static void *threadfunctiondata = "这是一个多线程定时器示例！";

//新线程开始标识，值为1时开始多线程
static int startflag = 0;
static int panelHandle;
int CVICALLBACK ThreadFunction (void *functionData);

int main (int argc, char *argv[])
{
 int threadID;
 if (InitCVIRTE (0, argv, 0) == 0)
  return -1; /* out of memory */
 if ((panelHandle = LoadPanel (0, "multi thread.uir", PANEL)) < 0)
  return -1;
 
 //创建一个新程函数
 CmtScheduleThreadPoolFunction (DEFAULT_THREAD_POOL_HANDLE, ThreadFunction, threadfunctiondata, &threadID);
 
 DisplayPanel (panelHandle);
 RunUserInterface ();
 
 //等待线程执行，直到结束
 CmtWaitForThreadPoolFunctionCompletion (DEFAULT_THREAD_POOL_HANDLE, threadID, OPT_TP_PROCESS_EVENTS_WHILE_WAITING);
 
 //释放线程函数
 CmtReleaseThreadPoolFunctionID (DEFAULT_THREAD_POOL_HANDLE, threadID);
 DiscardPanel (panelHandle);
 return 0;
}

int CVICALLBACK start (int panel, int control, int event,
  void *callbackData, int eventData1, int eventData2)
{
 int threadID;
 switch (event)
 {
  case EVENT_COMMIT:
   startflag = 1;
   CmtScheduleThreadPoolFunction (DEFAULT_THREAD_POOL_HANDLE, ThreadFunction, threadfunctiondata, &threadID);
   break;
 }
 return 0;
}

int CVICALLBACK stop (int panel, int control, int event,
  void *callbackData, int eventData1, int eventData2)
{
 switch (event)
 {
  case EVENT_COMMIT:
   startflag = 0;
   break;
 }
 return 0;
}

int CVICALLBACK QuitCallback (int panel, int control, int event,
  void *callbackData, int eventData1, int eventData2)
{
 switch (event)
 {
  case EVENT_COMMIT:
   startflag = 0; 
   QuitUserInterface (0);
   break;
 }
 return 0;
}

int CVICALLBACK ThreadFunction (void *functionData)
{
 double yarray[1];
 double result;
 while (startflag)
 {
  result = Random (0, 100);
  yarray[0] = result;
  PlotStripChart (panelHandle, PANEL_STRIPCHART, yarray, 1, 0, 0, VAL_DOUBLE);
  Delay (0.02);
  SetCtrlAttribute (panelHandle, PANEL_STRIPCHART, ATTR_LABEL_TEXT, (char *) functionData);
 } 
 return 0;
}

(1) CmtScheduleThreadPoolFunction这个函数的最后一个参数不是线程ID，而是线程函数ID，每一个线程都有一个线程函数实体，而该线程就执行对应的线程函数。当调用这个创建线程的函数的时候，线程函数就被调用了。

(2)CmtWaitForThreadPoolFunctionCompletion这个函数是等待线程函数执行完成。

(3)系统调度的最小单位为线程。

(4)当运行单线程程序时，如果程序进入了一个死循环，则不能进行其它的操作了，比如说拖拽运行的界面，而多线程可以。