OpenProcess 错误 87 无效参数
我正在尝试编写一个程序，该程序在当前目录中执行 MinGW 发行版中的 make.exe 并利用其 STDOUT 数据和退出代码。我有一个处理 STDOUT 的句柄，我从中获取数据，使用 CreatePipe 创建。当我在该管道上收到 ERROR_HANDLE_EOF 时，我假设进程已退出并尝试获取其退出代码：
if(session->pid == 0) return;
HANDLE hp = OpenProcess(PROCESS_QUERY_INFORMATION |
PROCESS_TERMINATE, TRUE, session->pid);
if(hp == NULL) {
printf("OpenProcess(%i) failed, error: %i\n",
session->pid, (int)GetLastError());
return;
}
我的代码适用于我测试的所有其他 MinGW 实用程序（如 pwd、ls 等），我得到 STDOUT 和退出代码没有问题。但是当我在 make 上尝试时，上面的代码显示以下消息：
“OpenProcess(2032) failed, error: 87”
我在 google 上搜索错误代码 87，它显示“无效参数”。我不知道像 2032 这样的正进程 ID 可能会无效。有什么想法吗？
I'm trying to write a program which executes make.exe from MinGW distribution in the current directory and makes use of its STDOUT data and exit code. I have a handle to process STDOUT where I fetch data from, created with CreatePipe. When I get an ERROR_HANDLE_EOF on that pipe I assume the process has exited and try to get its exit code:
if(session->pid == 0) return;
HANDLE hp = OpenProcess(PROCESS_QUERY_INFORMATION |
PROCESS_TERMINATE, TRUE, session->pid);
if(hp == NULL) {
printf("OpenProcess(%i) failed, error: %i\n",
session->pid, (int)GetLastError());
return;
}
My code works on all other MinGW utilities I tested (like pwd, ls, etc.), I get the STDOUT and the exit code with no problem. But when I try it on make, the above code displays the following message:
"OpenProcess(2032) failed, error: 87"
I googled for error code 87, and it says "Invalid parameter". I don't see what could be invalid about a positive process id like 2032. Any ideas?
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您应该使用来自
CreateProcess的句柄，而不是在 PID 上使用OpenProcess。OpenProcess仅当进程对象仍然存在时才有效。当您调用OpenProcess时，如果流程对象已消失 - 结果是使用无效参数的调用。您使用其他实用程序获得的成功要么是由于竞争条件（有时可能会失败），要么是您使子进程的原始句柄保持打开状态。
You should use the handle from
CreateProcessinstead of usingOpenProcesson the PID.OpenProcessonly works if the process object still exists. By the time you callOpenProcessif the process object is gone - the result is a call with invalid parameter.The success you got with other utilities is either due to a race condition (which may fail some times) or you kept the original handle to the child process open.
为了别人的目的而留下小费。我设法通过尝试打开以下内容来达到
ERROR_INVALID_PARAMETER (87)：当您例如从
GetWindowThreadProcessId直接，它是创建窗口的线程的标识符，而不是它的指针参数（它为您提供了请求的 PID）。Leaving a tip for someone else's purpose. I managed to reach the
ERROR_INVALID_PARAMETER (87)by trying to open:The second case may be a problem when you e.g. claim a result from
GetWindowThreadProcessIddirectly, which is anidentifier of the thread that created the window, instead of its pointer parameter (which gives you requested PID).虽然帖子很旧：我注意到当进程存在但由不同的用户和/或 Windows 桌面和/或终端服务器会话拥有时，我得到了
ERROR_INVALID_PARAMETER。奇怪的是，
WTSEnumerateProcess()函数不会遇到此错误，但成本要高得多，特别是在一个已经处于大量进程的重负载系统上（并且调用我的甚至耗尽 Windows 内核资源）。因此，不可能造成提供的“真实”无效参数和访问错误。我本来期望的是
ERROR_ACCESS_DENIED（但作为常规/非提升用户调用的任务管理器仍然显示所有进程）。看起来 Windows 中有些不一致？
Although the post is old: I noticed that I got
ERROR_INVALID_PARAMETERwhen the process existed, but owned by different user and/or Windows desktop and/or terminal server session.Strange enough, the
WTSEnumerateProcess()function does not suffer from this error, but is much more expensive, especially on a system that is already under heavy load with many processes (and a call my even exhaust windows kernel resources).So, it is not possible to make a 'real' invalid parameter provided and access errors. I would have expected
ERROR_ACCESS_DENIEDinstead (but a task manager invoked as regular/non-elevated user still shows all processes).Look like some inconsistencies in Windows?