Re: collect2 / gcc-2.95.2 / HP-UX 10.20 / global C++ objects in shared libs

[Jeffrey A Law <law at cygnus dot com>]

  In message <200003271558.RAA06310@takefive.co.at>you write:
  > collect2 on HP-UX never emits calls to {con,de}structors of global
  > C++ objects in shared libraries.  An example is shown at the bottom.
  > 
  > I traced collect2 in gdb and found that the following patch solves
  > the problem:
This patch is wrong.

We do not want collect2 to find and fire individual constructors for objects
in shared libraries.

Instead collectw2 is supposed to find the library's single constructor function
which is responsible for firing the individual constructors. 

Your problem is you used "ld" instead of "gcc" to build your shared
library and thus no ctor for the library as a whole was ever created.

jeff

  > 
  > *** gcc-2.95.2/gcc/collect2.c.orig   Tue Oct 12 23:16:52 1999
  > --- gcc-2.95.2/gcc/collect2.c        Tue Mar 21 17:20:24 2000
  > ***************
  > *** 2349,2359 ****
  >         {
  >         case 1:
  > !         if (which_pass != PASS_LIB)
  > !           add_to_list (&constructors, name);
  >           break;
  > 
  >         case 2:
  > !         if (which_pass != PASS_LIB)
  > !           add_to_list (&destructors, name);
  >           break;
  > 
  > --- 2349,2357 ----
  >         {
  >         case 1:
  > !         add_to_list (&constructors, name);
  >           break;
  > 
  >         case 2:
  > !         add_to_list (&destructors, name);
  >           break;
  > 
  > 
  > 
  > Reproduce like this:
  > 
  > shell> uname -a
  > HP-UX gismo B.10.20 A 9000/820 2004661727 two-user license
  > 
  > shell> cat String.h
  > 
  > #pragma interface
  > 
  > class String {
  >   const char * str;
  > public:
  >   String(const char *s);
  >   const char * GetStr();
  > };
  > 
  > extern String gString;
  > 
  > 
  > shell> cat String.cc
  > 
  > #pragma implementation
  > 
  > #include "String.h"
  > 
  > String gString ("global String");
  > 
  > String::String (const char * s)
  >   : str(s)
  > {
  > }
  > 
  > const char *
  > String::GetStr()
  > {
  >   return str;
  > }
  > 
  > 
  > shell> cat main.cc
  > 
  > #include <stdio.h>
  > #include "String.h"
  > 
  > int main ()
  > {
  >   const char * s = gString.GetStr();
  >   printf ("s = 0x%08X \"%s\"\n",
  >           (unsigned long) s,
  >           s ? s : "(null)");
  >   return 0;
  > }
  > 
  > 
  > shell> gcc -v
  > Reading specs from /opt/gnu/lib/gcc-lib/hppa1.1-hp-hpux10.20/2.95.2/specs
  > gcc version 2.95.2 19991024 (release)
  > shell> gcc -fpic -c String.cc
  > shell> ld -b -o libbase.sl String.o
  > shell> gcc -c String.cc
  > shell> ar rv libbase.a String.o
  > shell> gcc -o main.static main.cc libbase.a
  > shell> gcc -o main.shared main.cc libbase.sl
  > shell> ./main.static
  > s = 0x00002B60 "global String"
  > shell> ./main.shared
  > s = 0x00000000 "(null)"
  >