Re: How to setup a breakpoint on constructor

[Roland Zerek <rolandz at poczta dot fm>]

Użytkownik Michael Elizabeth Chastain napisał:

> See the PROBLEMS file:
>
>   gdb/1091: Constructor breakpoints ignored
>   gdb/1193: g++ 3.3 creates multiple constructors: gdb 5.3 can't set breakpoints

Well, I am using gdb-6.0 and gcc-3.4.0. Seems that problems remain...

>   When gcc 3.x compiles a C++ constructor or C++ destructor, it generates
>   2 or 3 different versions of the object code.  These versions have
>   unique mangled names (they have to, in order for linking to work), but
>   they have identical source code names, which leads to a great deal of
>   confusion.  Specifically, if you set a breakpoint in a constructor or a
>   destructor, gdb will put a breakpoint in one of the versions, but your
>   program may execute the other version.  This makes it impossible to set
>   breakpoints reliably in constructors or destructors [...]

However this is logical to have mangled names. And of course few 
constructors. Even ISO says that the default constructor may be created by 
the compiler in some situations...

> Things you can try:
>
> . modify your program so that the constructors that you want to
>   breakpoint call some function that is not a constructor, and break
>   on that.

I've already been considerring it.

> . run 'nm a.out | c++filt' to find the symbols in your program.
>   break on the absolute address: "break *0x01234567".  this is
>   very crude (1960's technique) but it does work.

Seems nice. However my MinGW (Win XP) seems not to have these. I will take 
a look of it later :-)

> . use nm, c++filt, and 'strip -N' to strip out symbols for
>   not-in-charge constructors.  This is scriptable, if someone
>   wants to write a little script.

What the "not-in-charge" means?

Thx for reply.

--
Roland
r o l a n d z (at) poczta fm