我受到 Daniel G. answer 的启发并实现了一个非常简单的用例 - 在我的工作中，我经常需要使用不同的参数重复调用相同的（外部）进程。我已经破解了一种方法来确定每个特定调用何时完成，但现在我有一种更简洁的方法来发出回调。
我喜欢这个实现，因为它非常简单，但它允许我向多个处理器发出异步调用（注意我使用multiprocessing 而不是threading）并在完成时收到通知。
我测试了示例程序，效果很好。请随意编辑并提供反馈。
import multiprocessing
import subprocess
class Process(object):
"""This class spawns a subprocess asynchronously and calls a
`callback` upon completion; it is not meant to be instantiated
directly (derived classes are called instead)"""
def __call__(self, *args):
# store the arguments for later retrieval
self.args = args
# define the target function to be called by
# `multiprocessing.Process`
def target():
cmd = [self.command] + [str(arg) for arg in self.args]
process = subprocess.Popen(cmd)
# the `multiprocessing.Process` process will wait until
# the call to the `subprocess.Popen` object is completed
process.wait()
# upon completion, call `callback`
return self.callback()
mp_process = multiprocessing.Process(target=target)
# this call issues the call to `target`, but returns immediately
mp_process.start()
return mp_process
if __name__ == "__main__":
def squeal(who):
"""this serves as the callback function; its argument is the
instance of a subclass of Process making the call"""
print "finished %s calling %s with arguments %s" % (
who.__class__.__name__, who.command, who.args)
class Sleeper(Process):
"""Sample implementation of an asynchronous process - define
the command name (available in the system path) and a callback
function (previously defined)"""
command = "./sleeper"
callback = squeal
# create an instance to Sleeper - this is the Process object that
# can be called repeatedly in an asynchronous manner
sleeper_run = Sleeper()
# spawn three sleeper runs with different arguments
sleeper_run(5)
sleeper_run(2)
sleeper_run(1)
# the user should see the following message immediately (even
# though the Sleeper calls are not done yet)
print "program continued"
样本输出：
program continued
finished Sleeper calling ./sleeper with arguments (1,)
finished Sleeper calling ./sleeper with arguments (2,)
finished Sleeper calling ./sleeper with arguments (5,)
下面是sleeper.c的源代码——我的示例“耗时”外部进程
#include<stdlib.h>
#include<unistd.h>
int main(int argc, char *argv[]){
unsigned int t = atoi(argv[1]);
sleep(t);
return EXIT_SUCCESS;
}
编译为：
gcc -o sleeper sleeper.c