MEI例程之 notify.c

1、thread对象

An MPIThread object provides a platform-independent method to create a thread, set its priority, and obtain its current status.
一个MPIThread对象提供一个平台独立的方法创建一个线程，设置它的优先级，并且获得当前的状态。

（1）方法：

A、创建、删除、验证方法

创建一个线程 

mpiThreadCreate(MPIThread        *thread,//指向一个MPIThread句柄

                    MPIThreadOptions *options);//thread线程的设置
创建一个thread对象，这个函数并不开启一个新的线程。在创建一个thread线程之后，使用mpiThreadStart开启一个线程。

删除一个线程 

MPI_DECL1 MPI_RESULT MPI_DECL2
    mpiThreadDelete(MPIThread thread);//指向一个MPIThread句柄
删除一个线程对象，并使线程句柄无效。这个函数并不终止一个线程。

验证一个线程对象和它的句柄： 

MPI_DECL1 MPI_RESULT MPI_DECL2

    mpiThreadValidate(MPIThread thread);//指向一个MPIThread句柄

B、配置方法和信息方法

开始一个新的线程：

MPI_DECL1 MPI_RESULT MPI_DECL2
    mpiThreadStart(MPIThread         thread,//指向一个MPIThread句柄
                   MPIThreadFunction function,   //线程调用函数
                   void              *argument);//传递给调用函数的参数

线程状态：

将线程的当前状态写到status中。

MPI_DECL1 MPI_RESULT MPI_DECL2
    mpiThreadStatus(MPIThread        thread,//指向一个MPIThread句柄
                    MPIThreadStatus  *status);//MPIThreadStatus指针

mpiThreadFunction ：

将线程函数指针传送到mpiThreadStart
MPI_DECL1 MPI_RESULT MPI_DECL2
    mpiThreadFunction(MPIThread          thread,
                      MPIThreadFunction *function);

mpiThreadArgument：

设置argument参数
MPI_DECL1 MPI_RESULT MPI_DECL2
    mpiThreadArgument(MPIThread   thread,
                      void        **argument);  /* see mpiThreadStart() */ 

mpiThreadPriorityGet 获得当前线程的优先级

MPI_DECL1 MPI_RESULT MPI_DECL2
    mpiThreadPriorityGet(MPIThread          thread,
                         MPIThreadPriority  *priority);

mpiThreadPrioritySet 设置线程的优先级

MPI_DECL1 MPI_RESULT MPI_DECL2
    mpiThreadPrioritySet(MPIThread         thread,
                         MPIThreadPriority priority);

（2）数据类型:

MPIThreadFunction

typedef MPI_RESULT (MPI_DECL2 *MPIThreadFunction)(void *threadData);

这时一个函数指针的类型别名，MPIThreadFunction是在一个新的线程中发起的函数指针。
使用此类型别名相同的签名，可以用作线程函数。
在线程函数中发生的异常不能传送到MPI库，这导致主线程退出，程序崩溃。
threadArgs 对象句柄（与controller关联，生成事件）。

MPIThreadOptions

typedef struct MPIThreadOptions {
int32_t     stackSize;
} MPIThreadOptions;
设置新线程的选项。stackSize 新线程的栈大小。

MPIThreadPriority

设置新线程与调用线程的优先级差别。MPIThreadPriorityDEFAULT 将新线程的优先级设置为调用线程的优先级。MPIThreadPriorityHIGHEST将线程的优先级设置为最高。

MPIThreadStatus 

MPIThread对象的状态信息

typedef struct MPIThreadStatus {
    void           *id;             /* platform-specific thread id ，事件的类型*/
    MPI_BOOL       active;          /* FALSE => thread not active ，线程的状态，如果是true，说明线程函数还没有完成，如果是false，说明线程函数已经完成。*/
    MPI_RESULT     returnValue;     /* thread-specific return value */
} MPIThreadStatus;

（3）示例：

MPI_RESULT MPI_DECL2    helloThreadMain(void* threadData)//主线程{    /* print event type to screen. 将事件类型打印到屏幕*/    printf("Hello from another thread.\n"           "  threadData = 0x%08x", threadData);    return MPIMessageOK;}/* Wait for a thread to end 等待线程结束*/MPI_RESULT threadJoin(MPIThread thread){    MPIThreadStatus status;    MPI_RESULT      returnValue = MPIMessageOK;    while (returnValue == MPIMessageOK)    {        returnValue = mpiThreadStatus(thread, &status);        if ((returnValue == MPIMessageOK) &&            (status.active == FALSE))//当为false时，说明次线程调用函数已经结束        {            break;        }       mpiPlatformSleep(10);    }    return returnValue;}void sayHello(){    MPIThread  thread;    MPI_RESULT returnValue;    returnValue = mpiThreadCreate(&thread, NULL);//创建线程    msgCHECK(returnValue);    returnValue = mpiThreadStart(thread, helloThreadMain, NULL);//开始线程，helloThreadMain是线程调用函数    msgCHECK(returnValue);    returnValue = threadJoin(thread);//等待线程结束，这个函数会一直循环，直到线程调用函数结束    msgCHECK(returnValue);     returnValue = mpiThreadDelete(thread);//删除线程    msgCHECK(returnValue);}

主程序

/* notify1.c *//*:Create notify object and wait for events.Create a thread that uses a notify object to wait for user-defined eventspassed to the notify object from the main thread.创建一个线程，使用notify对象等待在主线程中传送过来的事件，这个事件是用户自定义的*/#include <stdlib.h>#include <stdio.h>#include <string.h>#include "stdmpi.h"#include "apputil.h"#if defined(ARG_MAIN_RENAME)#define main    notify1MainargMainRENAME(main, notify1)#endif/* Command line arguments and defaults */Arg argList[] = {{   NULL,       ArgTypeINVALID, NULL,   }};Static  int32_t    NotifyWaitAwake;//线程调用函数完成标志Static int32_tnotifyWait(MPINotify notify);//线程调用函数intmain(int    argc, char   *argv[]){MPIControl  control;        /* Motion controller handle */MPINotify   notify;         /* Event notification object */MPIEventMask    eventMask;MPI_RESULT returnValue;int32_t    eventDone;MPIControlType      controlType;MPIControlAddress   controlAddress;int32_t    argIndex;MPIThread          thread;//定义线程MPIThreadStatus    status;//线程状态argIndex =argControl(argc,argv,&controlType,&controlAddress);/* Parse command line for application-specific arguments */while (argIndex < argc) {int32_t    argIndexNew;argIndexNew = argSet(argList, argIndex, argc, argv);if (argIndexNew <= argIndex) {argIndex = argIndexNew;break;}else {argIndex = argIndexNew;}}/* Check for unknown/invalid command line arguments */if (argIndex < argc) {mpiPlatformConsole("usage: %s %s\n",argv[0],ArgUSAGE);exit(MPIMessageARG_INVALID);}/* Create motion controller object */returnValue =mpiControlCreate(&control,controlType,&controlAddress);msgCHECK(returnValue);/* Request notification of ALL events */mpiEventMaskCLEAR(eventMask);mpiEventMaskALL(eventMask);/* Create event notification object */returnValue =mpiNotifyCreate(¬ify,eventMask,NULL);msgCHECK(returnValue);returnValue= mpiThreadCreate(control, &thread, NULL);//创建线程对象if (returnValue == MPIMessageOK) {returnValue =mpiThreadStart(thread,(MPIThreadFunction)notifyWait,//线程调用函数notify);//开始这个线程}eventDone = FALSE;//事件完成标志，false表示未完成while ((returnValue == MPIMessageOK) &&(eventDone == FALSE)) {char    buffer[128];int32_t    index;int32_t    haveEventNumber;/* Wait for notifyWait() to call mpiNotifyEventWait() */while (NotifyWaitAwake != FALSE) {//线程调用函数唤醒标志mpiPlatformSleep(1);}/* Make sure notifyWait() thread is still executing */returnValue =mpiThreadStatus(thread,&status);if (returnValue != MPIMessageOK) {break;}if (status.active == FALSE) {//线程调用函数完成，退出循环break;}mpiPlatformConsole("Enter an event number, or ESC to exit ...\n");memset(buffer, 0, sizeof(buffer));//分配内存index = 0;haveEventNumber = FALSE;//有无事件标志while (haveEventNumber == FALSE) {MPIEventData  eventStatus;int32_t    key;int32_t    eventNumber = 0;key = mpiPlatformKey(MPIWaitFOREVER);if (key <= 0) {mpiPlatformKey(MPIWaitFOREVER);continue;}switch (key) {case 0x1b: {    /* ESC */eventNumber = key;haveEventNumber = TRUE;eventDone = TRUE;break;   }case '\r':case '\n': {mpiPlatformConsole("\n");eventNumber = mpiPlatformAtol(buffer);haveEventNumber = TRUE;break;   }case '\b': {if (index > 0) {mpiPlatformConsole("\b \b");buffer[--index] = '\0';}break;   }case '-': {if (index == 0) {buffer[index++] = (char)key;mpiPlatformConsole("%c", key);}break;  }case '0':case '1':case '2':case '3':case '4':case '5':case '6':case '7':case '8':case '9': {buffer[index++] = (char)key;mpiPlatformConsole("%c", key);break;  }default: {break; }}if (haveEventNumber != FALSE) {NotifyWaitAwake = TRUE;eventStatus.eventType    = MPIEventTypeSEQUENCE;eventStatus.objectIndex = eventNumber;returnValue =mpiNotifyEventWake(notify,&eventStatus);}}}if (thread != NULL) {while (returnValue == MPIMessageOK) {returnValue =mpiThreadStatus(thread,&status);msgCHECK(returnValue);if (status.active == FALSE) {returnValue = status.returnValue;break;}mpiPlatformSleep(1);}returnValue = mpiThreadDelete(thread);msgCHECK(returnValue);}fprintf(stderr,"%s exiting: returnValue 0x%x: %s\n",argv[0],returnValue,mpiMessage(returnValue, NULL));returnValue = mpiNotifyDelete(notify);msgCHECK(returnValue);returnValue = mpiControlDelete(control);msgCHECK(returnValue);return ((int)returnValue);}Static int32_tnotifyWait(MPINotify notify)//线程调用函数{MPI_RESULT returnValue;MPIWait timeout;int32_t    eventDone;/* Validate the notify object and its handle */returnValue = mpiNotifyValidate(notify);timeout = MPIWaitFOREVER;eventDone = FALSE;while ((returnValue == MPIMessageOK) &&(eventDone == FALSE)) {MPIEventData  eventStatus;NotifyWaitAwake = FALSE;/* Wait for notify event */returnValue =mpiNotifyEventWait(notify,&eventStatus,timeout);mpiPlatformConsole("mpiNotifyEventWait(0x%x, 0x%x, %d) returns 0x%x: %s\n",notify,&eventStatus,timeout,returnValue,mpiMessage(returnValue, NULL));switch (returnValue) {case MPIMessageOK: {mpiPlatformConsole("\teventStatus: type %d number %d\n",eventStatus.eventType,eventStatus.objectIndex);if (eventStatus.objectIndex == 0x1b) {eventDone = TRUE;}break;   }case MPIMessageTIMEOUT: {mpiPlatformConsole("\tTIMEOUT\n");break;}default: {break; }}}mpiPlatformConsole("notifyWait(0x%x) returning 0x%x: %s\n",notify,returnValue,mpiMessage(returnValue, NULL));return (returnValue);}