On approximately 11/29/2003 3:28 AM, came the following characters from
the keyboard of Laurent ROCHER:
Glenn,
I try to merge and apply your patch on 665-Fix branch this week-end.
I quick read your patch and i see this :
! #ifdef PERLWIN32GUI_GLBREAK
! printf("XS(Create): %s\n", perlcs.cs.lpszName );
! if ( perlcs.cs.lpszName
! && strcmp ( perlcs.cs.lpszName, "findlist.pl Main Window" ) == 0 )
! { __asm { int 3 };
! }
! #endif
It's a debugger breakpoint !!!!!
Some time ago, i search a way to debug a XS code whitout find.
It's very usefull, i test it and it's work great with Visual C++.
Thank for this "Tip Of The Day" ;o)
Laurent.
Yeah, I took out most (not all) of my debugging code of the nature of
#ifdef SOME_SYMBOL_MOST_PEOPLE_WONT_HAVE
printf( "something or another\n" );
#endif
but when I got to that one, I thought it might be useful for someone
that hadn't ever seen it done before. I love debuggers, but they can be
real contrary to use with dynamically created code, such as Perl and
other interpreters... in such situations, starting from the top, one
needs to set a number of breakpoints along the way, after code get
created and/or loaded, just to find your way in to where you really want
to set the breakpoint. It can often be much easier to instrument the
code you want to debug with the breakpoint in the manner above, but
unless one understands the assembly language and the debugger itself to
some extent, it can be difficult to figure that out!
Yes, it does work well with Visual C; some other debuggers, since they
did not place the breakpoint there, may get somewhat confused about
discovering one there... for those debuggers, often the way they express
their confusion is to attempt to "reexecute" the "int 3" instruction.
To sidestep their confusion, use the debugger commands to increment the
instruction pointer ( reg IP = IP + 1 ) although the syntax varies
between debuggers, and sometimes might be click here or there and type
the new number (it would be in Visual C, if Visual C didn't handle it
reasonably).
--
Glenn -- http://nevcal.com/
===========================
Like almost everyone, I receive a lot of spam every day, much of it
offering to help me get out of debt or get rich quick. It's ridiculous.
-- Bill Gates
And here is why it is ridiculous:
The division that includes Windows posted an operating profit of $2.26
billion on revenue of $2.81 billion.
--from Reuters via
http://biz.yahoo.com/rc/031113/tech_microsoft_msn_1.html
So that's profit of over 400% of investment... with a bit more
investment in Windows technology, particularly in the area of
reliability, the profit percentage might go down, but so might the bugs
and security problems? Seems like it would be a reasonable tradeoff.
WalMart earnings are 3.4% of investment.
