标签：end unix print 爬虫 parent ror err tpi nbsp
一、多进程
1.fork方法（os模块,适用于Lunix系统）
fork方法：调用1次，返回2次。原因：操作系统经当前进程（父进程）复制出一份进程（子进程），两个进程几乎完全相同，fork方法分别在父进程、子进程中返回，子进程返回值为0，父进程中返回的是子进程的ID。
普通方法：调用1次，返回1次
import os if __name__ == ‘__main__‘: print ‘current Process (%s) start ....‘%(os.getpid()) #getpid()用户获取当前进程ID pid = os.fork() if pid <0: print ‘error in fork‘ elif pid == 0: print ‘I am child process (%s)‘ and my parent process is (%s)‘,(os.getpid(),os.getppid()) else: print ‘I (%s) created a child process (%s).‘,(os.getpid(),pid) 运行结果如下： current Process (3052) start .... I (3052) created a child process (3053). I am child process (3053) and my parent process is (3052)
2.multiprocessing（跨平台）
import os # 从multiprocessing模块中导入Process类 from multiprocessing import Process def run_proc(name): print ‘Child process %s (%s) Running...‘ % (name,os.getpid()) if __name__ == ‘__main__‘: print ‘Parent process %s.‘ % os.getpid() for i in range(5): p = Process(target = run_proc,args = (str(i),)) print ‘Process will start‘ #用于启动进程 p.start() # 用于实现进程间的同步 p.join() print ‘Process end‘ 执行结果如下： Parent process 2392. Process will start. Process will start. Process will start. Process will start. Process will start. Child process 2 (10748) Runing... Child process 0 (5324) Runing... Child process 1 (3196) Runing... Child process 3 (4680) Runing... Child process 4 (10696) Runing... Process end
标签：end unix print 爬虫 parent ror err tpi nbsp
原文地址：https://www.cnblogs.com/loser1949/p/9215498.html
