如何重定向子进程的标准输出？

发布于 2024-08-19 13:42:38 字数 754 浏览 4 评论 0原文

def StartProc(dir, parm):
    global proc    

    proc_log = open(dir + os.sep + "MyLog.txt","w")  #new path for each file

    if parm:
        proc = subprocess.Popen(path, 0, None, subprocess.PIPE, proc_log, None)
    else:
        MyReset(proc)                     #reset the process(proc) to its default values
        proc.stdout = proc_log            #no effect
        print "fptr ", proc.stdout
    #endif
#enddef

prm = True

for i in range(0, 5):
    StartProc(i, prm)
    prm = False
#endfor

我想做的是仅启动一次可执行文件，但在每次迭代中我想将进程输出重定向到不同的文件。发生的情况是，文件是在不同的路径中创建的，但输出被重定向到第一次创建的文件。

注意：MyReset() 在第一次迭代后将进程（可执行文件）初始化为其默认值。

以下行会将进程标准输出更改为新文件吗？

proc.stdout = proc_log

原文

def StartProc(dir, parm):
    global proc    

    proc_log = open(dir + os.sep + "MyLog.txt","w")  #new path for each file

    if parm:
        proc = subprocess.Popen(path, 0, None, subprocess.PIPE, proc_log, None)
    else:
        MyReset(proc)                     #reset the process(proc) to its default values
        proc.stdout = proc_log            #no effect
        print "fptr ", proc.stdout
    #endif
#enddef

prm = True

for i in range(0, 5):
    StartProc(i, prm)
    prm = False
#endfor

What I want to do is to start an executable only once, but on each iteration I want to redirect the process output to a different file. What is happening, is that files are created in the different path, but output is redirected to the file that is created first time.

Note: MyReset() initializes the process (executable) to its default values after the first iteration.

Will the following line change the process stdout to new file?

proc.stdout = proc_log

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谁对谁错谁最难过 2024-08-26 13:42:38

就像 unwind 所说的那样，您无法更改子进程将其输出写入其中的文件描述符。

您可以做的是读取 python 脚本中子进程的输出，然后将其写回到您想要的任何文件中。例如：

proc = subprocess.Popen(path, 0, None, subprocess.PIPE, subprocess.PIPE, None)

for l in proc.stdout.readlines():
  output_file.write(l)

显然，您需要弄清楚控制在您的应用程序中应如何表现，即您可以从主线程进行写入吗？在这种情况下主线程何时应从 StartProc() 返回，或者您是否必须从另一个线程进行写入，以便主线程可以立即从 StartProc() 返回。

Like unwind said, you cannot change the file descriptor that the child process is writing its output to.

What you can do, is read the output from the child process in your python script and then write it back to whatever file you want to. E.g.:

proc = subprocess.Popen(path, 0, None, subprocess.PIPE, subprocess.PIPE, None)

for l in proc.stdout.readlines():
  output_file.write(l)

Obivously, you'll need to figure out how control should behave in your app, i.e. can you do the writing from the main thread, when should the main thread return from StartProc() in that case, or do you have to do the writing from another thread so that the main thread can return from StartProc() immediately.

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