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[英]WaitForSingleObject on a semaphore does not wait, returns immediately
[英]Waitforsingleobject works when trying to open Notepad++ but returns immediately with Firefox
我有以下代碼,這些代碼使用CreateProcess打開一個應用程序,等待它幾秒鍾,如果未關閉,則將其關閉。 例如,相同的代碼在notepad ++上可以正常運行,但是在我嘗試打開Firefox.exe時卻無法正常運行
BOOL CALLBACK SendWMCloseMsg(HWND hwnd, LPARAM lParam)
{
//never gets called when opening Firefox.exe
DWORD dwProcessId = 0;
GetWindowThreadProcessId(hwnd, &dwProcessId);
if (dwProcessId == lParam)
SendMessageTimeout(hwnd, WM_CLOSE, 0, 0, SMTO_ABORTIFHUNG, 30000, NULL);
return TRUE;
}
int main()
{
STARTUPINFO si;
PROCESS_INFORMATION pi;
memset(&si, 0, sizeof(si));
memset(&pi, 0, sizeof(pi));
si.cb = sizeof(si);
WCHAR szFilename[] = L"C:\\Program Files\\Mozilla Firefox\\firefox.exe";
if (CreateProcess(NULL,
szFilename,
NULL,
NULL,
FALSE,
CREATE_DEFAULT_ERROR_MODE,
NULL,
NULL,
&si,
&pi))
{
CloseHandle(pi.hThread);
WaitForInputIdle(pi.hProcess, INFINITE);
auto a = WaitForSingleObject(pi.hProcess, 30000);
if (a == WAIT_TIMEOUT)
{
EnumWindows(&SendWMCloseMsg, pi.dwProcessId);
if (WaitForSingleObject(pi.hProcess, INFINITE) == WAIT_TIMEOUT)
{
//never gets here.
TerminateProcess(pi.hProcess, 0);
}
}
//a vlaue is 0 and it never gets in the if statement.
CloseHandle(pi.hProcess);
}
return 0;
}
SendWMCloseMsg
不被調用,當我刪除if語句並調用EnumWindows(&SendWMCloseMsg, pi.dwProcessId);
,它仍然找不到正確的processId。
我在用此代碼做錯什么以及如何解決此問題?
我正在使用Windows 10、64位和VS2015
答案是,您從CreateProcess
開始的進程創建了許多其他進程-然后退出。
您的WaitForSingleObject
成功完成,並且程序結束。
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