GetOpenFileName fails with access violation. File must be on DESKTOP and have long name. Problem occurs only after first successful open of the file. Problem occurs when mouse cursor hovers over file as tool tip about to be displayed.
See the answer below. I'm leaving the original problem description below.
Mike D.
=======================
I'm using GetOpenFileName. I sometimes get a access violation deep inside shell32. The violation never occurs the first time this code is used, it often takes five or six tries. Also it appears that if one selects a file in second or two after the open file window pops up, the violation does not occur. Also, the call stack displayed when I debug this does not include any of my code. It's as if some independent thread is waking up to do something.
Any insights into how I might debug this greatly appreciated!
I made a "hello" world app exhibiting the same behavior. It, however, requires many more tries before it fails. It also seems that one has to switch directories before it will fail.
The GOFN is done from a thread created just for that purpose. Below is the code from the "hello world" app.
typedef struct
{
public:
HWND hWnd;
HINSTANCE hInst;
} def_params, *p_params;
DWORD WINAPI ReadLogFile_DataRecorderThread (PVOID pvoid);
void ReadLogFile_DataRecorder (HWND hWnd, HINSTANCE hInst) // ***************************
{
static def_params Params;
Params.hWnd = hWnd;
Params.hInst = hInst;
HANDLE T = CreateThread (NULL,0,ReadLogFile_DataRecorderThread,&Params,0,NULL);
CloseHandle (T);
return;
}
DWORD WINAPI ReadLogFile_DataRecorderThread (PVOID pvoid)
{
p_params P = (p_params) pvoid;
HWND hWnd = P->hWnd;
HINSTANCE hInst = P->hInst;
char ReadLogFileLastDir[256];
// static def_OpenFileHook Hook;
OPENFILENAME ofn;
char fn[MAX_PATH]="\0";
char filter[32]="Text Files\0*.TXT;\0\0";
char title[]="Open IMC Data Recorder Log File";
char defext[]="TXT";
int status;
// Get File Name
fn[0] = '\0';
ReadLogFileLastDir[0] = '\0';
ZeroMemory(&ofn, sizeof(ofn));
ofn.lStructSize = sizeof(ofn);
ofn.hwndOwner = hWnd;
ofn.hInstance = hInst;
ofn.hInstance = (HINSTANCE) GetWindowLong (hWnd, GWL_HINSTANCE);
ofn.lpstrFilter = filter;
ofn.nFilterIndex = 0;
ofn.lpstrCustomFilter = NULL ;
ofn.nMaxCustFilter = 0 ;
ofn.lpstrFile = fn;
ofn.nMaxFile = sizeof(fn);
ofn.lpstrFileTitle = NULL;
if (ReadLogFileLastDir[0] == '\0')
{
SHGetSpecialFolderPath (NULL,ReadLogFileLastDir,0x0005,false);
};
ofn.lpstrInitialDir = ReadLogFileLastDir;
ofn.lpstrTitle = title;
ofn.Flags = OFN_FILEMUSTEXIST |
OFN_PATHMUSTEXIST |
OFN_EXPLORER |
// OFN_ENABLETEMPLATE |
OFN_ENABLESIZING |
// OFN_ENABLEHOOK |
OFN_READONLY;
ofn.lpstrDefExt = NULL;
ofn.lpfnHook = NULL; // Hook.DialogHook; // hook routine
ofn.lCustData = NULL; // (long) &Hook; // data for hook routine
ofn.lpTemplateName = NULL; // MAKEINTRESOURCE(IDD_HOOKFILEOPEN);
ofn.nFileOffset = 0 ;
ofn.nFileExtension = 0 ;
ofn.lpstrDefExt = defext;
status = GetOpenFileName (&ofn);
int S;
S = CommDlgExtendedError();
return 0;
}
When it fails, the call stack looks like this...
SHELL32! 7ca4e035()
SHELL32! 7cb2dc16()
SHELL32! 7cb2dd5a()
SHELL32! 7cb27361()
SHELL32! 7c9f40a3()
BROWSEUI! 75f81b9a()
SHLWAPI! 77f69548()
NTDLL! 7c927545()
NTDLL! 7c927583()
NTDLL! 7c927645()
NTDLL! 7c92761c()
KERNEL32! 7c80b50b()
Sorry but I am unable to get symbols for these as I have an old Visual C++ :-(
It appears to me that the problem occurs when the GOFN stuff is about to open the popup describing the file as the mouse cursor hovers over the file name.
The set of circumstances causing the problem are somewhat weird. Experiments show one has to do the following in the GOFN window:
- Open a file on the DESKTOP
- Hover over a long file name
If I do this twice, it always fails. The file name I used was
IMCLOG_20120323_1658_-_20120324_0653_CST_+DST_E2_2_second.TXT
I tried the same thing with NOTEPAD and the same problem occurs!
