当我设置标准输出时调用 subprocess.call 挂起 [英] Calling subprocess.call hangs when I set the stdout

问题描述

我有一个函数，我称之为程序，带有一些参数并想得到结果.

I have a function which I call a progarm, with some args and want to get the result.

当我使用以下内容时

proc = subprocess.call(["fetch.py", "--cookies=/tmp/tmp-cookies"], stdout=PIPE, stderr=PIPE)
stdout, stderr = proc.communicate()
return stdout

应用程序只是挂起.但是如果我跑

The app just hangs. But if I run

return subprocess.call(["fetch.py", "--cookies=/tmp/tmp-cookies"])

然后我在屏幕上获得输出并且应用程序运行良好，但是我需要将输出输入到函数中.

then I get the output on my screen and the app works fine, however I need to get the output into a function.

我使用的是 python 2.6.1，无法使用 check_output

I am using python 2.6.1, and unable to use check_output

推荐答案

作为 规范说，

不要将 stdout=PIPE 或 stderr=PIPE 与此函数一起使用.由于当前进程没有读取管道，如果子进程生成足够的输出到管道以填满操作系统管道缓冲区，它可能会阻塞.

Do not use stdout=PIPE or stderr=PIPE with this function. As the pipes are not being read in the current process, the child process may block if it generates enough output to a pipe to fill up the OS pipe buffer.

你需要的是subprocess.Popen:

proc = subprocess.Popen(["fetch.py", "--cookies=/tmp/tmp-cookies"], 
                       stdout=PIPE, stderr=PIPE)
stdout, stderr = proc.communicate()
return stdout

(另外，subprocess.call 不返回进程对象，只返回退出状态)

(Also, subprocess.call does not return the process object, only exit status)

这篇关于当我设置标准输出时调用 subprocess.call 挂起的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！