EXC_BAD_INSTRUCTION when using NSRunAlertPanel - objective-c

Question

To show errors on some condition, I am using NSRunAlertPanel on Mac OS X (on the code which is ported from Windows, where I was using MessageBox).
Before actual creation of Windows, some code is being run and calling this code to show some conditional error.
In a thread com.apple.libdispatch-manager, under following call stack
0 _dispatch_mgr_invoke
1 _dispatch_mgr_thread
it is giving EXC_BAD_INSTRUCTION
Is it because Windows is not created before NSRunAlertPanel?
What is the reason of this runtime error? What is exact alternative of MessageBox on Mac OS X?
Long ShowDebugMessageBox (const wchar_t * Message, const wchar_t * Title)
{
NSString * message; ///< Message.
NSString * title; ///< Title.
NSInteger response; ///< response.
message = WideToNSString (Message);
title = WideToNSString (Title);
//response = NSRunAlertPanel(title, message, #"Yes", #"No", #"Cancel");
response = NSRunCriticalAlertPanel (title, message, #"Okay", #"Cancel", nil);
switch(response) {
case NSAlertDefaultReturn:
return IDYES;
case NSAlertAlternateReturn:
return IDNO;
default:
return IDCANCEL;
}
}
NSString * WideToNSString (const wchar_t * Str)
{
if(!Str) {
return nil;
}
NSString * str; ///< String in NSString.
#if CP_SIZEOFWCHAR == 4
str = [[NSString alloc] initWithBytes: (CVPtr) Str
length: sizeof(wchar_t)* wcslen(Str)
encoding: NSUTF32LittleEndianStringEncoding];
//encoding: NSUTF32StringEncoding];
#else
str = [[NSString alloc] initWithBytes: (CVPtr) Str
length: sizeof(wchar_t)* wcslen(Str);
encoding: NSUTF16LittleEndianStringEncoding];
//encoding: NSUTF16StringEncoding];
#endif
return str;
}
class File {
public:
int Open(char * fname, int mode)
{
fd = open(fname, mode);
}
int Close()
{
close(fd);
//fd = 0; //CAUSE of the PROBLEM
}
~File ()
{
//ALERT Display message box about the error.
ALERT(fd != 0);
}
private:
int fd;
};
This is the code to show the message box.
Code to get NSString from wchar_t * string (Wide string) is perfectly fine and was tested. It is used in many places and running fine.
Same code on the other application (which creates Window first) is running fine.
Problem occurs when the destructor of File is called. Since fd is not 0, it shows message box and cause the problem.
When fd is set to 0, no alert box is displayed for constructor. However, other alert are shown but no problem occurred.
Is it due fd?

Answer 1

You haven't provided enough information to say what is causing the exception (please show the code).
I use NSRunCriticalAlertPanel() to display fatal errors in my app, which I am able to call pretty much any time I like:
void criticalAlertPanel(NSString *title, NSString *fmt, ...)
{
va_list va;
va_start(va, fmt);
NSString *message = [[NSString alloc] initWithFormat:fmt arguments:va];
va_end(va);
NSRunCriticalAlertPanel(title, message, #"OK", nil, nil);
}
(this code is ARC enabled).