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From: rfg@NCD.COM (Ron Guilmette)
Newsgroups: comp.lang.c++,gnu.g++.bug,gnu.g++.lib.bug
Subject: Re: problems with calling streams from constructors
Message-ID: <1206@lupine.NCD.COM>
Date: 16 Aug 90 07:34:13 GMT
References: <38170@ucbvax.BERKELEY.EDU>
Followup-To: comp.lang.c++
Organization: Network Computing Devices, Inc., Mt. View, CA
Lines: 40

In article <38170@ucbvax.BERKELEY.EDU> jbuck@galileo.berkeley.edu (Joe Buck) writes:
<With g++ (1.37.1) and libg++ (1.37.0) the following code results in a fatal
<error when the MyClass constructor is called for globalObj:
<
[ ... code ommitted ... ]
<
<The error occurs because global objects are initialized in the order
<that object modules are handed to the linker, and cerr is not yet
<initialized when the constructor for globalObj is called.  As a result,
<the ostream::operator<<(whatever) function dereferences null pointers.
<
<I know I can work around this problem by searching libg++ twice; I
<also have a workaround that causes gnulib3.c to call the constructors
<in reverse order.  Reverse order always works when everything but main()
<is obtained from a library and there are no circular dependencies.

If there are circular dependencies, you are in big trouble no matter which
order the initializations get done in!

Also, you seem to be suggesting that there will be some problem(s) with
this nice simple approach if you do not pull everything except main()
from some library.  I don't see why you are worried about it.  It can work
fine even if you are linking some arbitrary collection of .o files and .a
files in some arbitrary order (as long as your linking order is
consistant with the partial ordering imposed by the initialization
dependencies).

<Still, it's an inelegant hack.

What makes you think so?  I happen to believe the exact opposite, i.e.
that it is elegant precisely because it works, it is simple, and it
still allows the user the user a maximal level of control (via specifying
some desired linking order).

Do you have a better solution?
-- 

// Ron Guilmette  -  C++ Entomologist
// Internet: rfg@ncd.com      uucp: ...uunet!lupine!rfg
// Motto:  If it sticks, force it.  If it breaks, it needed replacing anyway.