HJ's patch to libio works on Red Hat 4.2/libc 5.3.12

[H.J. Lu]

> 
> Joe Buck <jbuck@synopsys.com> writes:
> > I installed HJ's patch, as modified according to Ulrich's suggestion,
> > and all libio tests pass on a straight Red Hat 4.2 system.
> 
> Same here.
> 
> I seem to have an additional problem however. The attched stripped
> down code core dumps on a i386-linux-gnulibc1 box with libc 5.3.12 
> (RH 4.2). I've also attched the backtrace from gdb.
> 
> I've applied Jason's and HLJ's patches to date to egcs-971008.
> 
> To run it, create a text file "data.in" with a floating point number in
> it.
> 
> =====
> #include <fstream.h>
> #include <cstdlib>
> 
> int main () {
>   ifstream ifp ("data.in");
>   if (!ifp) {
>     cerr << "Error opening input \"data.in\"" << endl;
>     exit (1);
>   }
> 
>   double dummy;
>   ifp >> dummy;			// <<<<<<< CORE DUMPS HERE
>   if (!ifp) {
>     cerr << "Error reading input \"data.in\"" << endl;
>     exit (1);
>   }
> 
>   exit (1);
> }
> =====
> 
> Here's the back trace:
> 
> % c++  -g -o ifstream ifstream.cc
> % gdb ifstream
> GDB is free software and you are welcome to distribute copies of it
>  under certain conditions; type "show copying" to see the conditions.
> There is absolutely no warranty for GDB; type "show warranty" for details.
> GDB 4.16 (i586-unknown-linux), Copyright 1996 Free Software Foundation,
> Inc...
> (gdb) r
> Starting program: /tmp/ifstream 
> warning: Unable to find dynamic linker breakpoint function.
> warning: GDB will be unable to debug shared library initializers
> warning: and track explicitly loaded dynamic code.
> 
> Program received signal SIGSEGV, Segmentation fault.
> 0x4002dc12 in ostream::flush (this=0x40030bfc)
>     at ../../../libio/iostream.cc:854
> 854         if (_strbuf->sync())
> (gdb) bt
> #0  0x4002dc12 in ostream::flush (this=0x40030bfc)
>     at ../../../libio/iostream.cc:854
> #1  0x4002ccd3 in istream::operator>> (this=0xbffffa28, x=@0xbffff9cc)
>     at ../../../libio/iostream.h:159
> #2  0x8048ae0 in main () at ifstream.cc:12
> #3  0x80489db in ___crt_dummy__ ()
> #4  0x4002b2f8 in __tf8ifstream () at ../../../libio/fstream.h:61
> Cannot access memory at address 0xffa0.
> (gdb) 
> 
> 

I think somehow your libstdc++ is miscompiled.

-- 
H.J. Lu (hjl@gnu.ai.mit.edu)