Re: Class throwing exceptions in aggregate static initializer causes abort() ...
Thank you very much, Mr. Steinbach,
Alf P. Steinbach je napisao/la:
* Marvin Barley:
I have a class that throws exceptions in new initializer, and a static
array of objects of this type.
When something is wrong in initialization, CGI program crashes
miserably. Debugging shows uncaught exception.
How to catch an exception that happened before main() try { ... }
catch (...) { ... } block?
Is there a way?
Locally yes, just use try-catch; globally, in a portable way, no.
I thought there should be a way through set_terminate() to just exit
gracefully, if not to actually catch exception?
That said, what you have doesn't seem to be exceptions resulting from
exceptional circumstances (such as resource shortage), but resulting
from programming bugs.
No, Sir, stack unwinding proved that the abort() was called in a stack
child of __cxa_throw() called from
__static_initialization_and_destruction_0() internals.
Should've printed it out:
=========================================
#0 0x00003aa431af7545 in raise () from /lib/libc.so.6
#1 0x00003aa431af8cce in abort () from /lib/libc.so.6
#2 0x00003aa4316f85c6 in __cxa_call_unexpected () from /usr/lib/
libstdc++.so.5
#3 0x00003aa4316f85f3 in std::terminate () from /usr/lib/libstdc++.so.
5
#4 0x00003aa4316f8713 in __cxa_throw () from /usr/lib/libstdc++.so.5
#5 0x0000000000406124 in formtblitem::initialize (this=0x50b6e0,
ff=0x62 <Address 0x62 out of bounds>, ft=0x407ffb "b", df=0x408043
"5",
mn=0x408007 "0", mx=0x407e5e "1", ps=0x408052 "AA")
at povdriver-0.1.64-cgi.cc:197
#6 0x0000000000405d29 in __static_initialization_and_destruction_0 (
__initialize_p=3, __priority=16071) at povdriver-0.1.64-cgi.cc:252
#7 0x0000000000407996 in __do_global_ctors_aux ()
#8 0x0000000000402483 in _init ()
#9 0x0000000000407910 in __libc_csu_init ()
#10 0x00000000004078cb in __libc_csu_init ()
#11 0x00003aa431ae53eb in __libc_start_main () from /lib/libc.so.6
#12 0x0000000000402aea in _start () at ../sysdeps/x86_64/elf/start.S:
96
#13 0x000079001d77e7e8 in ?? ()
#14 0x0000000000000000 in ?? ()
#15 0x0000000000000001 in ?? ()
#16 0x000079001d77e9ce in ?? ()
#17 0x0000000000000000 in ?? ()
#18 0x000079001d77e9e7 in ?? ()
#19 0x000079001d77e9f7 in ?? ()
#20 0x000079001d77ea03 in ?? ()
#21 0x000079001d77ea2c in ?? ()
#22 0x000079001d77ea4b in ?? ()
#23 0x000079001d77ea5e in ?? ()
#24 0x000079001d77ea6c in ?? ()
#25 0x000079001d77eca1 in ?? ()
#26 0x000079001d77f16c in ?? ()
#27 0x000079001d77f1be in ?? ()
#28 0x000079001d77f1d6 in ?? ()
#29 0x000079001d77f1ec in ?? ()
#30 0x000079001d77f214 in ?? ()
#31 0x000079001d77f21f in ?? ()
#32 0x000079001d77f238 in ?? ()
#33 0x000079001d77f240 in ?? ()
#34 0x000079001d77f258 in ?? ()
#35 0x000079001d77f269 in ?? ()
#36 0x000079001d77f288 in ?? ()
#37 0x000079001d77f291 in ?? ()
..
..
..
===========================================
Fix your code and you won't have that problem.
I'll try - if only I could know for sure from inside constructor is
the object statically or dynamically initialized, so I should throw
exception in dynamic allocation and only set <error_code> in static
case?
Thank you very much in forward,
Marvin
class formtblitem {
protected:
void clear() {
memset (form_field, 0, sizeof (form_field ));
memset (field_type, 0, sizeof (field_type ));
memset (dflt, 0, sizeof (dflt ));
memset (minval, 0, sizeof (minval ));
memset (maxval, 0, sizeof (maxval ));
memset (POVRAYsubst, 0, sizeof (POVRAYsubst));
varaddr = NULL;
}
memset is not guaranteed to yield C++ nullvalues, and is dangerous and
generally inefficient (when wielded by novices) -- not that you should
focus on effiency at all before having reasonably /correct/ code.
Here's a reasonable and correct implementation of clear(), assuming a
default constructor that clears:
void clear() { *this = formtblitem(); }
Don't use raw arrays (even though this code also works with raw arrays).
#define STRCPY(DEST, SRC) > > if (strlen (SRC) > sizeof (DEST) - 1) > > throw PARM_ESTRBUFOVERFLOW; > > else > > strcpy (DEST, SRC);
Don't use macros.
Couldn't find a way to check sizeof () elegant in function, sorry I
know some very competent programmers who use macros. I think it is a
matter of opinion.
Don't use raw pointers.
Don't use macros.
Reserve all uppercase names for macros (which you shouldn't use) --
see this group's FAQ and Bjarne Stroustrup's FAQ.
Additional errors probably in the declarations you left out.
No need to use keyword 'class' -- C'ism.
No need to use keyword 'class' -- not even a C'ism.
I think these are just style guides not connected to the main problem
of exception in global initializer, wouldn't you agree? I like to
emphasize it is a class in declaration, since I have a short term
memory problem ;-)
It might be a good idea to reproduce in a small program that compiles,
and post that code.
Should've thought of it myself:
#include <iostream>
using namespace std;
class formtblitem {
void initialize (const char *val) {
throw -1;
form_field = new char [strlen(val)+1];
strcpy (form_field, val);
}
protected:
char *form_field;
public:
formtblitem() { form_field = NULL; }
formtblitem(char *line) { initialize (line); }
~formtblitem() {
if (form_field) delete [] form_field;
}
const char * FormField (void)
{ return form_field; }
};
typedef formtblitem FTI;
FTI formtbl[] = {
FTI ("global initializer throwing exceptions")
};
int main (int argc, char *argv[]) {
FTI *dynamic = NULL;
try {
FTI automatic("automatic_initializer");
dynamic = new FTI("dynamic_initializer");
} catch (int i) {
cout << "caught exception << i << endl;
// cleanup
if (dynamic) delete [] dynamic;
exit(1);
}
}
-------------------------------------
Thanks!