gdb/342: No symbol "<var>" in current context for C++ variable declared in if block after try/catch

[galexander at nc dot rr dot com]

>Number:         342
>Category:       gdb
>Synopsis:       No symbol "<var>" in current context for C++ variable declared in if block after try/catch
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Feb 05 22:08:01 PST 2002
>Closed-Date:
>Last-Modified:
>Originator:     Geoff Alexander
>Release:        GNU gdb 5.1
>Organization:
>Environment:
SuSE Linux for i386 7.1
gcc 2.95.2 as shipped with SuSE 7.1 (gcc-2.95.2-151)
>Description:
When trying to print a variable in a C++ program declared
in a if block which occurs after a try/catch, I get a

  No symbol "<var>" in current context.

error.

The following program illustrates the problem:

  #include <cstdlib>
  #include <exception>
  #include <iostream>
  #include <string>
  int main( int argc, char* argv[] )
  {
    try
    {
      string d = "This is d";
    }
    catch (std::exception& e)
    {
      cout << "std::exception caught" << endl;
      exit(EXIT_FAILURE);
    }
    string a = "This is a";
    if ( a == "" )
    {
      string b = "This is b";
      cout << a << endl;
      cout << b << endl;
      cout << b.c_str() << endl;
    }
    else
    {
      string c = "This is c";
      cout << a << endl;
      cout << c << endl;
    }
    exit(EXIT_SUCCESS);
  }

I compiled the above program as follows:

  g++ -g -o Test2 Test2.cppg

Using gdb to debug, I get a

   No symbol "c" in current context.

error as follows:

  GNU gdb 5.1
  Copyright 2001 Free Software Foundation, Inc.
  GDB is free software, covered by the GNU General Public License, and you are
  welcome to change it and/or 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.
  This GDB was configured as "i686-pc-linux-gnu"...
  (gdb) break 27
  Breakpoint 1 at 0x804a14e: file Test2.cpp, line 27.
  (gdb) run
  Starting program: /home/gdlxn/gdb_bugs/001/Test2
 
  Breakpoint 1, main (argc=1, argv=0xbffff7cc) at Test2.cpp:27
  27          cout << a << endl;
  (gdb) print c
  No symbol "c" in current context.

If I comment out the the try/catch as follows:

  #include <cstdlib>
  #include <exception>
  #include <iostream>
  #include <string>
  int main( int argc, char* argv[] )
  {
    //  try
    //  {
    //    string d = "This is d";
    //  }
    //  catch (std::exception& e)
    //  {
    //    cout << "std::exception caught" << endl;
    //    exit(EXIT_FAILURE);
    //  }
    string a = "This is a";
    if ( a == "" )
    {
      string b = "This is b";
      cout << a << endl;
      cout << b << endl;
      cout << b.c_str() << endl;
    }
    else
    {
      string c = "This is c";
      cout << a << endl;
      cout << c << endl;
    }
    exit(EXIT_SUCCESS);
  }

recompile as follows:

  g++ -g -o Test3 Test3.cpp

and debug using gdb, I am able to print c:

  GNU gdb 5.1
  Copyright 2001 Free Software Foundation, Inc.
  GDB is free software, covered by the GNU General Public License, and you are
  welcome to change it and/or 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.
  This GDB was configured as "i686-pc-linux-gnu"...
  (gdb) break 27
  Breakpoint 1 at 0x804a01c: file Test3.cpp, line 27.
  (gdb) run
  Starting program: /home/gdlxn/gdb_bugs/001/Test3
   
  Breakpoint 1, main (argc=1, argv=0xbffff7cc) at Test3.cpp:27
  27          cout << a << endl;
  (gdb) print c
  $1 = {static npos = 4294967295, static nilRep = {len = 0, res = 0, ref = 1,
      selfish = false}, dat = 0x804cad8 "This is c"}
>How-To-Repeat:

>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted: