阻止版本的execvp(Windows) [英] Blocking version of execvp (windows)

问题描述

此问题与 system()的非阻止版本完全相反

我想用另一个过程代替当前过程(而不创建另一个过程).

I want to substitute the current process by another one (not create another one).

我想启动(例如)notepad，但是以一种阻塞的方式(我不想在关闭notepad之前得到提示.

I want to start (for instance) notepad, but in a blocking way (I don't want to get the prompt until notepad is closed.

在Windows shell中，我只是做

In the Windows shell I just do

cmd /c notepad

((notepad如果不带cmd /c前缀则自动与提示分离)

(notepad auto-detachs from prompt if not prefixed by cmd /c)

在C语言中，我只是使用system

In C, using system I just do

system("notepad");

但这是幕后花絮.我想用notepad 替换当前进程，并且希望它被阻止.

But this is forking behind the scenes. I want to replace the current process by notepad, and I want it to be blocking.

我尝试过:

#include <stdio.h>
#include <unistd.h>

int main(int argc,char **argv)
{
  char * const args[] = {"cmd","/c","notepad",NULL};
  execvp(args[0],args);
}

notepad运行，但控制台立即返回提示.(非阻塞).我希望它阻止，并且我不想使用fork，因为它会创建另一个进程:我想替换当前进程.

notepad runs, but the console returns to the prompt immediately.(non-blocking). I want it to block, and I don't want to use fork as it would create another process: I want to replace the current process.

(我尝试过使用自定义阻止可执行文件，但它也不会阻止.因此cmd /c notepad示例与其他任何示例一样好)

(I have tried with a custom blocking executable, and it doesn't block either. So cmd /c notepad example is as good as any other one)

因此，如果我运行此可执行文件，那么我只是从父进程中构建的:

So, If I run this executable I just built from a parent process:

• 在notepad进程退出之前，我不希望该进程返回到父进程.
• 我希望能够从命令中获取输出(在这种情况下，notepad不是一个很好的例子)
• 我不想创建额外的流程(这是大型多处理应用程序的一部分，我们无力创建2个流程，每次运行都需要保留1个流程)

• I don't want the process to return to the parent process until the notepad process exits
• I want to be able to get output from the command (notepad isn't a good example in that case)
• I don't want to create an extra process (this is part of a massive multiprocessing application, we can't afford to create 2 processes, we need to keep 1 process for each run)

有可能吗?

推荐答案

目前尚不清楚您想要什么-如果当前子进程由子可执行文件替换了 ，则当前进程将无法等待子进程通过execv*()函数.

It's not exactly clear what you want - the current process can't wait on the child process if it's replaced by the child executable via an execv*() function.

在Windows上可能的system()替代品是

A possible system() replacement - on Windows - is _spawnvp():

intptr_t _spawnvp(  
   int mode,  
   const char *cmdname,  
   const char *const *argv   
);  

只需使用

int rc = _spawnvp( _P_WAIT, command, args );

(我怀疑此确切功能在POSIX系统上不可用的原因是，它很容易通过fork()，exec*()和wait()的变体在POSIX上实现.与Windows等效的功能要多一些复杂.)

(I suspect the reason this exact functionality isn't available on POSIX systems is that it's easily implemented on POSIX via fork(), exec*(), and a variation of wait(). Windows equivalents of those are a bit more complex.)

使用Windows _spawn*()函数时要注意的一件事是文件名中带有空格.我在通过此函数传递此类文件名时遇到了一些实际问题，不得不对其进行引用.

One thing to be careful of when using Windows _spawn*() functions is filenames with spaces in them. I've had some real issues passing such filenames via this function and had to quote them.

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