Re: Iostream deadlock...

[Fons Rademakers <Fons dot Rademakers at cern dot ch>]

Hi Martin,

   here a quite small demonstration program showing the deadlock.
I hope you now will do something with the problem.

Another observation, if you remove the RTLD_GLOBAL flags it always works
so the problem must be related to some symbol exported by the pthreads lib.


Cheers, Fons.


//------------- tb.cxx ----------------
// On linux compile with: g++ -o tb tb.cxx -ldl
#include <iostream.h>
#include <fstream.h>
#include <dlfcn.h>

int main()
{
   const char *fname = "tb.cxx";
   int c;
   ifstream file0(fname);
   //c = file0.get();    // call get() before loading pthread
                         // and the problem disappears
   // load libpthread.so
   void *handle = dlopen("/usr/lib/libpthread.so", RTLD_GLOBAL | RTLD_LAZY);
   if (!handle) {
      cerr << "dlopen error" << endl;
      return 1;
   }

   ifstream file1(fname);
   if (!file1) {
      cerr << "Cannot open file " << fname << endl;
      return 1;
   }

   c = file1.get();  // remove first character   <-- deadlock here

   char line[256];

   file1 >> ws;   // eat whitespace
   file1 >> line;

   cout << "First token is: " << line << endl;

   return 0;
}


"Martin v. Loewis" wrote:
> 
> >   could somebody tell me the status of the dealock problem in iostreams?
> 
> It is the first time I heard about the problem.
> 
> > Any change this will be fixed soon?
> 
> That's unlikely. Without seeing the source, I'd assume that it is a
> bug in the application, or a problem where the application relies on
> things that are not guaranteed by the implementation. It is not even
> clear to me whether your problem is the same one as Bob Glickstein's:
> even though the symptoms are similar, the causes could be different.
> 
> IOW, nobody will do anything with that problem unless there is an
> example demonstrating it.
> 
> Regards,
> Martin

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