Sampel Program Multithread C

Bounce.c adalah contoh program multithread yang membuat utas baru setiap kali huruf a atau A ditik. Setiap utas memantulkan huruf dengan warna yang berbeda di sekitar layar. Hingga 32 utas dapat dibuat. Penghentian normal program terjadi ketika q atau Q dititik.

Mengkompilasi dan menautkan program multithread

Program dikompilasi sebagai multithreaded secara default.

Untuk mengompilasi dan menautkan program multithread Bounce.c dari dalam lingkungan pengembangan

1. Pada menu File, pilih Proyek>Baru.

2. Dalam dialog Buat proyek baru, pilih templat Aplikasi Konsol yang memiliki tag C++, Windows, dan Konsol. Pilih Berikutnya untuk melanjutkan.

3. Dalam dialog Konfigurasikan proyek baru Anda, masukkan nama untuk proyek Anda, seperti "Bounce". Pilih Buat untuk melanjutkan.

4. Di jendela Penjelajah Solusi, buka folder File Sumber di bawah proyek Anda, dan ubah nama file sumber Anda agar memiliki ekstensi .c.

5. Di jendela edit, hapus kode sumber yang ada dan ganti dengan kode sampel.

6. Pada menu Build, pilih Buat Solusi.

7. Tekan F5 untuk memulai program di debugger.

Untuk mengompilasi dan menautkan program multithread Bounce.c dari baris perintah

1. Buka perintah alat Visual Studio. Ini memastikan jalur diatur untuk menyertakan pengkompilasi.

2. Kompilasi dan tautkan program:

   cl bounce.c
   

Contoh

Untuk membangun pada baris perintah, salin dan simpan sampel ini dalam file sumber dengan ekstensi .c. Di IDE, ganti kode sumber apa pun yang dibuat oleh templat dengan sampel ini:

// sample_multithread_c_program.c
// compile with: /c
//
//  Bounce - Creates a new thread each time the letter 'a' is typed.
//  Each thread bounces a character of a different color around
//  the screen. All threads are terminated when the letter 'Q' is
//  entered.
//

#include <windows.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <conio.h>
#include <process.h>

#define MAX_THREADS  32

// The function getrandom returns a random number between
// min and max, which must be in integer range.
#define getrandom( min, max ) (SHORT)((rand() % (int)(((max) + 1) - \
                               (min))) + (min))

int main(void);                    // Thread 1: main
void KbdFunc(void);                // Keyboard input, thread dispatch
void BounceProc(void* pMyID);      // Threads 2 to n: display
void ClearScreen(void);            // Screen clear
void ShutDown(void);               // Program shutdown
void WriteTitle(int ThreadNum);    // Display title bar information

HANDLE  hConsoleOut;                 // Handle to the console
HANDLE  hRunMutex;                   // "Keep Running" mutex
HANDLE  hScreenMutex;                // "Screen update" mutex
int     ThreadNr = 0;                // Number of threads started
CONSOLE_SCREEN_BUFFER_INFO csbiInfo; // Console information
COORD   consoleSize;
BOOL    bTrails = FALSE;

HANDLE  hThreads[MAX_THREADS] = { NULL }; // Handles for created threads

int main(void) // Thread One
{
    // Get display screen information & clear the screen.
    hConsoleOut = GetStdHandle(STD_OUTPUT_HANDLE);
    GetConsoleScreenBufferInfo(hConsoleOut, &csbiInfo);
    consoleSize.X = csbiInfo.srWindow.Right;
    consoleSize.Y = csbiInfo.srWindow.Bottom;
    ClearScreen();
    WriteTitle(0);

    // Create the mutexes and reset thread count.
    hScreenMutex = CreateMutexW(NULL, FALSE, NULL);  // Cleared
    hRunMutex = CreateMutexW(NULL, TRUE, NULL);      // Set

    // Start waiting for keyboard input to dispatch threads or exit.
    KbdFunc();

    // All threads done. Clean up handles.
    if (hScreenMutex) CloseHandle(hScreenMutex);
    if (hRunMutex) CloseHandle(hRunMutex);
    if (hConsoleOut) CloseHandle(hConsoleOut);
}

void ShutDown(void) // Shut down threads
{
    // Tell all threads to die
    ReleaseMutex(hRunMutex);

    while (ThreadNr > 0)
    {
        // Wait for each thread to complete
        WaitForSingleObject(hThreads[--ThreadNr], INFINITE);
    }

    // Clean up display when done
    WaitForSingleObject(hScreenMutex, INFINITE);
    ClearScreen();
}

void KbdFunc(void) // Dispatch and count threads.
{
    int         KeyInfo;

    do
    {
        KeyInfo = _getch();
        if (tolower(KeyInfo) == 'a' &&
            ThreadNr < MAX_THREADS)
        {
            ++ThreadNr;
            hThreads[ThreadNr] = 
                (HANDLE)_beginthread(BounceProc, 0, (void*)(uintptr_t)ThreadNr);
            WriteTitle(ThreadNr);
        }

        if (tolower(KeyInfo) == 't')
        {
            bTrails = !bTrails;
        }
    } while (tolower(KeyInfo) != 'q');

    ShutDown();
}

void BounceProc(void* pMyID)
{
    wchar_t MyCell, OldCell;
    WORD    MyAttrib, OldAttrib = 0;
    wchar_t BlankCell = 0x20;
    COORD   Coords, Delta;
    COORD   Old = { 0,0 };
    DWORD   Dummy;
    int MyID = (int)(uintptr_t)pMyID;

    // Generate update increments and initial
    // display coordinates.
    srand(MyID * 3);

    Coords.X = getrandom(0, consoleSize.X - 1);
    Coords.Y = getrandom(0, consoleSize.Y - 1);
    Delta.X = getrandom(-3, 3);
    Delta.Y = getrandom(-3, 3);

    // Set up character & generate color
    // attribute from thread number.
    if (MyID > 16)
        MyCell = (wchar_t)(0x60 + MyID - 16); // lower case
    else
        MyCell = (wchar_t)(0x40 + MyID);      // upper case
    MyAttrib = MyID & 0x0f;   // force black background

    do
    {
        // Wait for display to be available, then lock it.
        WaitForSingleObject(hScreenMutex, INFINITE);

        if (!bTrails)
        {
            // If we still occupy the old screen position, blank it out.
            ReadConsoleOutputCharacterW(hConsoleOut, &OldCell, 1,
                Old, &Dummy);
            ReadConsoleOutputAttribute(hConsoleOut, &OldAttrib, 1,
                Old, &Dummy);
            if ((OldCell == MyCell) && (OldAttrib == MyAttrib))
                WriteConsoleOutputCharacterW(hConsoleOut, &BlankCell, 1,
                    Old, &Dummy);
        }

        // Draw new character, then clear screen lock
        WriteConsoleOutputCharacterW(hConsoleOut, &MyCell, 1,
            Coords, &Dummy);
        WriteConsoleOutputAttribute(hConsoleOut, &MyAttrib, 1,
            Coords, &Dummy);
        ReleaseMutex(hScreenMutex);

        // Increment the coordinates for next placement of the block.
        Old.X = Coords.X;
        Old.Y = Coords.Y;
        Coords.X += Delta.X;
        Coords.Y += Delta.Y;

        // If we are about to go off the screen, reverse direction
        if (Coords.X < 0 || Coords.X >= consoleSize.X)
        {
            Delta.X = -Delta.X;
            Beep(400, 50);
        }
        if (Coords.Y < 0 || Coords.Y > consoleSize.Y)
        {
            Delta.Y = -Delta.Y;
            Beep(600, 50);
        }
    }
    // Repeat while RunMutex is still taken.
    while (WaitForSingleObject(hRunMutex, 75L) == WAIT_TIMEOUT);
}

void WriteTitle(int ThreadNum)
{
    enum
    {
        sizeOfNThreadMsg = 120
    };
    wchar_t    NThreadMsg[sizeOfNThreadMsg] = { L"" };

    swprintf_s(NThreadMsg, sizeOfNThreadMsg,
        L"Threads running: %02d.  Press 'A' "
        L"to start a thread, 'T' to toggle "
        L"trails, 'Q' to quit.", ThreadNum);
    SetConsoleTitleW(NThreadMsg);
}

void ClearScreen(void)
{
    DWORD    dummy = 0;
    COORD    Home = { 0, 0 };
    FillConsoleOutputCharacterW(hConsoleOut, L' ',
        consoleSize.X * consoleSize.Y,
        Home, &dummy);
}

Baca juga

Multithreading dengan C dan Win32