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C++执行命令行、获取命令行输出

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本文字数： 1.7k 阅读时长 ≈ 2 分钟
  1. 老方法，使用_popen
  2. 使用CreateProcess配合管道输出
  3. 时间对比

老方法，使用_popen

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std::string GetCmdResult(const std::string& cmd)
{
	char buf[1024] = { 0 };
	FILE* pf = _popen(cmd.c_str(), "r");
	if (nullptr == pf)
	{
        OutputDebugString("open pipe failed");
		return "";
    }
    
	std::string ret;
	while (fgets(buf, sizeof(buf), pf))
	{
		ret += buf;
	}

	_pclose(pf);
	return ret;
}

使用CreateProcess配合管道输出

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std::string GetCmdResult(const std::string& cmd)
{
	// 创建读写管道
	SECURITY_ATTRIBUTES sa;
	ZeroMemory(&sa, sizeof(SECURITY_ATTRIBUTES));
	sa.nLength = sizeof(SECURITY_ATTRIBUTES);
	sa.lpSecurityDescriptor = NULL;
	sa.bInheritHandle = TRUE;
	HANDLE hReadPipe, hWritePipe;
	if (!CreatePipe(&hReadPipe, &hWritePipe, &sa, 0))
	{
		OutputDebugString("管道创建失败！");
		return "";
	}

	// 创建进程监控
	BOOL ret = FALSE;
	STARTUPINFO si;
	PROCESS_INFORMATION pi;
	ZeroMemory(&si, sizeof(STARTUPINFO));
	ZeroMemory(&pi, sizeof(PROCESS_INFORMATION));
	si.cb = sizeof(STARTUPINFO);
	si.dwFlags |= STARTF_USESTDHANDLES;
	si.hStdInput = NULL;
	si.hStdError = hWritePipe;
	si.hStdOutput = hWritePipe;

	ret = CreateProcess(NULL, const_cast<char*>(cmd.c_str()), NULL, NULL, TRUE, CREATE_NO_WINDOW, NULL, NULL, &si, &pi);

	if (ret)
	{
		CloseHandle(hWritePipe);

		std::string resStr;
		char pBuf[BUFFER_SIZE] = { 0 };
		DWORD readSize = 0;
		while (ReadFile(hReadPipe, pBuf, BUFFER_SIZE, &readSize, NULL))
		{
			resStr += pBuf;
			ZeroMemory(pBuf, BUFFER_SIZE);
		}
		CloseHandle(hReadPipe);
		CloseHandle(pi.hProcess);
		CloseHandle(pi.hThread);

		return resStr;
	}
	else
	{
		CloseHandle(hWritePipe);
		CloseHandle(hReadPipe);
		return "";
	}
}

时间对比

  • _popen: 350ms左右
  • CreateProcess: 50ms左右