java - C语言如何为特定任务编写像多线程一样的Java？它可以作为 objective-c 来完成吗？

Question

我们如何创建多线程或进程？跨平台使用C语言？并在需要时关闭线程。一次编写部署Linux/Windows/Mac/Android/MeeGo等平台。

Java 示例: runnable = new Mytest();线程=新线程(可运行)；

Step 1:
    runnable = new Mytest();
    thread = new Thread(runnable);

Step 2:

public class Mytest implements Runnable
{
  private static volatile boolean running = true
  public void run()
  {
    while(running) 
    { // do stuff }
  }
  public void start() { running = true; }
  public void stop()  { running = false;}
}

跟进:

第一步:vim omp_hello.c ( https://computing.llnl.gov/tutorials/openMP/exercise.html )

#include <omp.h>
#include <stdio.h>
#include <stdlib.h>

int main (int argc, char *argv[]) 
{
  int nthreads, tid;
  #pragma omp parallel private(nthreads, tid)
  {

    /* Obtain thread number */
    tid = omp_get_thread_num();
    printf("Hello World from thread = %d\n", tid);

    /* Only master thread does this */
    if (tid == 0) 
    {
      nthreads = omp_get_num_threads();
      printf("Number of threads = %d\n", nthreads);
    }

  }  /* All threads join master thread and disband */

}

第二步:$ gcc -fopenmp omp_hello.c -o hello

第 3 步:$ setenv OMP_NUM_THREADS 4

第四步:$./hello

Hello World from thread = 0 
Number of threads = 4
Hello World from thread = 3
Hello World from thread = 1
Hello World from thread = 2

完成。它有效!

Answer 1

C语言中没有线程的概念。大多数平台都有自己特定的线程库或 API(显然有些平台根本不支持线程)。

但是，第 3 方库，例如 OpenMP存在，它在一定程度上提供独立于平台的线程。