ddd 3.3.11 hangs when attached to a program with unbound output

[Eric Hattemer]

Both:
GNU DDD 3.3.11 (sparc-sun-solaris2.8)
Copyright (C) 1995-1999 Technische Universität Braunschweig, Germany.
Copyright (C) 1999-2001 Universität Passau, Germany.
Copyright (C) 2001 Universität des Saarlandes, Germany.
Copyright (C) 2001-2004 Free Software Foundation, Inc.

Compiled with GCC 3.3.2
Requires X11R6, Xt11R6, Motif 2.1 (Motif Version 2.1.0)
Includes XPM 3.4.7, Athena Panner, DDD core, Readline 5.0
Built 2007-11-21 by ehatteme <ehatteme@mesa.usc.edu>.

and

GNU DDD 3.3.11 (sparc-sun-solaris2.10)
Copyright (C) 1995-1999 Technische Universität Braunschweig, Germany.
Copyright (C) 1999-2001 Universität Passau, Germany.
Copyright (C) 2001 Universität des Saarlandes, Germany.
Copyright (C) 2001-2004 Free Software Foundation, Inc.

Compiled with GCC 4.2.1
Requires X11R6, Xt11R6, Motif 2.1 (Motif Version 2.1.0)
Includes XPM 3.4.7, Athena Panner, DDD core, Readline 5.0
Built 2008-08-28 by ehatteme <ehatteme@sol.usc.edu>.

hang if they run a program that prints to stdout in an infinite loop.  
This only occurs if the stdout is going to the gdb pane at the bottom of 
ddd.  If the program is run in a execution window, it prints fine, and 
can be interrupted.  The program can be interrupted in straight gdb.  It 
seems that the bug is related to the handling/buffering of the gdb pane 
at the bottom of ddd.

Here is the c++ code that causes the hang after entering an input >2:

#include <iostream>

using namespace std;

// finds all of n's factors
// not including 1 and itself
void factors (int n)
{
 int k = 2;
 while (k < n) {
   if (n % k == 0) {
     cout << k << " ";
   }
 }
}

int main()
{
 int n;
 cout << "Find factors of what number? ";
 cin >> n;
 cout << "Factors of n are: " << endl;
 factors (n);
 cout << endl;
}

Attached is .ddd/log with most of the 2's cut out of it.

-Eric Hattemer



GNU DDD 3.3.11 (sparc-sun-solaris2.8)
Copyright (C) 1995-1999 Technische Universität Braunschweig, Germany.
Copyright (C) 1999-2001 Universität Passau, Germany.
Copyright (C) 2001 Universität des Saarlandes, Germany.
Copyright (C) 2001-2004 Free Software Foundation, Inc.

Compiled with GCC 3.3.2
Requires X11R6, Xt11R6, Motif 2.1 (Motif Version 2.1.0)
Includes XPM 3.4.7, Athena Panner, DDD core, Readline 5.0
Built 2007-11-21 by ehatteme <ehatteme@mesa.usc.edu>.
$  ddd ./factors
+  /bin/sh -c 'exec gdb -q -fullname '\''./factors'\'''
#  Hello, world!
#  Starting GDB...
#  Running GDB (pid 27377, tty /dev/pts/1)...
#  Current language: C/C++
#  Searching "vsllib/ddd.vsl"...
#  Trying "/home/sol-00/ehatteme/.ddd/vsllib/ddd.vsl"
#  Trying "/usr/usc/ddd/3.3.11/share/ddd-3.3.11/vsllib/ddd.vsl"
#  Searching 
"vsllib/ddd.vsl"..."/usr/usc/ddd/3.3.11/share/ddd-3.3.11/vsllib/ddd.vsl".
#  Another DDD is running (pid 28218, host bb-dev1.usc.edu, display 
localhost:10.0)
2008.08.28 20:51:12
<- "(gdb) "
2008.08.28 20:51:12
-> "set prompt (gdb) \n"
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<- "(gdb) "
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-> "set height 0\n"
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<- "(gdb) "
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-> "set width 0\n"
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<- "(gdb) "
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-> "set annotate 1\n"
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<- "(gdb) "
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-> " set verbose off\n"
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<- "(gdb) "
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-> "info line\n"
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<- "No line number information available.\n"
   "(gdb) "
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-> "list\n"
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<- "16\t    \n"
   "17\t  }\n"
   "18\t\n"
   "19\t}\n"
   "20\t\n"
   "21\tint main()\n"
   "22\t{\n"
   "23\t  int n;\n"
   "24\t\n"
   "25\t  cout << \"Find factors of what number? \";\n"
2008.08.28 20:51:12
<- "(gdb) "
2008.08.28 20:51:12
-> "info line\n"
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<- "Line 25 of \"factors.cpp\" starts at address 0x10cb0 <main+4> and ends at 
0x10cc8 <main+28>.\n"
   "\032\032/home/sol-00/ehatteme/factors.cpp:25:257:beg:0x10cb0\n"
   "(gdb) "
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-> "output 4711\n"
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<- "4711"
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<- "(gdb) "
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-> "show language\n"
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<- "The current source language is \"auto; currently c++\".\n"
   "(gdb) "
2008.08.28 20:51:12
-> "show version\n"
2008.08.28 20:51:12
<- "GNU gdb 6.8\n"
   "Copyright (C) 2008 Free Software Foundation, Inc.\n"
   "License GPLv3+: GNU GPL version 3 or later 
<http://gnu.org/licenses/gpl.html>\n"
   "This is free software: you are free to change and redistribute it.\n"
   "There is NO WARRANTY, to the extent permitted by law.  Type \"show 
copying\"\n"
   "and \"show warranty\" for details.\n"
   "This GDB was configured as \"sparc-sun-solaris2.10\".\n"
   "(gdb) "
2008.08.28 20:51:12
-> "pwd\n"
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<- "Working directory /home/sol-00/ehatteme.\n"
   "(gdb) "
2008.08.28 20:51:12
-> "info breakpoints\n"
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<- "No breakpoints or watchpoints.\n"
   "(gdb) "
2008.08.28 20:51:12
-> "show history filename\n"
2008.08.28 20:51:12
<- "The filename in which to record the command history is 
\"/home/sol-00/ehatteme/.gdb_history\".\n"
   "(gdb) "
2008.08.28 20:51:12
-> "show history size\n"
2008.08.28 20:51:12
<- "The size of the command history is 256.\n"
   "(gdb) "
#  Reading file "/home/sol-00/ehatteme/factors.cpp"...
#  Reading file "/home/sol-00/ehatteme/factors.cpp"...done.
#  File "/home/sol-00/ehatteme/factors.cpp" 30 lines, 409 characters
#  Setting buttons...
#  Setting buttons...done.
2008.08.28 20:51:12
-> "info source\n"
2008.08.28 20:51:12
<- "Current source file is factors.cpp\n"
   "Compilation directory is /home/sol-00/ehatteme\n"
   "Located in /home/sol-00/ehatteme/factors.cpp\n"
   "Contains 30 lines.\n"
   "Source language is c++.\n"
   "Compiled with DWARF 2 debugging format.\n"
   "Does not include preprocessor macro info.\n"
   "(gdb) "
2008.08.28 20:51:12
-> "info files\n"
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<- "Symbols from \"/home/sol-00/ehatteme/factors\".\n"
   "Local exec file:\n"
2008.08.28 20:51:12
<- "\t`/home/sol-00/ehatteme/factors\', file type elf32-sparc.\n"
   "\tEntry point: 0x10998\t0x000100d4 - 0x000100e5 is .interp\n"
   "\t0x000100e8 - 0x0001024c is .hash\n"
   "\t0x0001024c - 0x0001050c is .dynsym\n"
   "\t0x0001050c - 0x0001085a is .dynstr\n"
   "\t0x0001085c - 0x0001089c is .SUNW_version\n"
   "\t0x0001089c - 0x000108c0 is .rela.got\n"
   "\t0x000108c0 - 0x000108e4 is .rela.bss\n"
   "\t0x000108e4 - 0x00010998 is .rela.plt\n"
   "\t0x00010998 - 0x00010e74 is .text\n"
   "\t0x00010e74 - 0x00010e90 is .init\n"
   "\t0x00010e90 - 0x00010ea4 is .fini\n"
   "\t0x00010ea8 - 0x00010eeb is .rodata\n"
   "\t0x00010eec - 0x00010ef0 is 
.gnu.linkonce.r._ZNSt15basic_streambufIcSt11char_traitsIcEE13_S_pback_sizeE\n"
   "\t0x00020ef0 - 0x00020f18 is .got\n"
   "\t0x00020f18 - 0x00021000 is .plt\n"
   "\t0x00021000 - 0x000210e0 is .dynamic\n"
   "\t0x000210e0 - 0x000210ec is .data\n"
   "\t0x000210ec - 0x000210f8 is .ctors\n"
   "\t0x000210f8 - 0x00021104 is .dtors\n"
   "\t0x00021104 - 0x000211b0 is .eh_frame\n"
   "\t0x000211b0 - 0x000211b4 is .jcr\n"
   "\t0x000211b4 - 0x000211b8 is .data.rel.local\n"
   "\t0x000211b8 - 0x000211b9 is 
.gnu.linkonce.d._ZN16__Atomicity_lockILi0EE17_S_atomicity_lockE\n"
   "\t0x000211c0 - 0x00021300 is .bss\n"
   "(gdb) "
2008.08.28 20:51:12
-> "info program\n"
2008.08.28 20:51:12
<- "The program being debugged is not being run.\n"
   "(gdb) "
2008.08.28 20:51:12
-> "set confirm off\n"
2008.08.28 20:51:12
<- "(gdb) "
2008.08.28 20:51:12
-> "source /var/tmp//dddZJa4D1\n"
2008.08.28 20:51:12
<- "(gdb) "
2008.08.28 20:51:12
-> "info breakpoints\n"
2008.08.28 20:51:12
<- "No breakpoints or watchpoints.\n"
   "(gdb) "
2008.08.28 20:51:12
-> "# reset\n"
2008.08.28 20:51:12
<- "(gdb) "
2008.08.28 20:51:12
-> "info breakpoints\n"
2008.08.28 20:51:12
<- "No breakpoints or watchpoints.\n"
   "(gdb) "
2008.08.28 20:51:12
-> "display\n"
2008.08.28 20:51:12
<- "(gdb) "
2008.08.28 20:51:12
-> "info display\n"
2008.08.28 20:51:12
<- "There are no auto-display expressions now.\n"
   "(gdb) "
2008.08.28 20:51:12
-> "set environment TERM dumb\n"
2008.08.28 20:51:12
<- "(gdb) "
2008.08.28 20:51:12
-> "info files\n"
2008.08.28 20:51:13
<- "Symbols from \"/home/sol-00/ehatteme/factors\".\n"
   "Local exec file:\n"
   "\t`/home/sol-00/ehatteme/factors\', file type elf32-sparc.\n"
   "\tEntry point: 0x10998\t0x000100d4 - 0x000100e5 is .interp\n"
   "\t0x000100e8 - 0x0001024c is .hash\n"
   "\t0x0001024c - 0x0001050c is .dynsym\n"
   "\t0x0001050c - 0x0001085a is .dynstr\n"
   "\t0x0001085c - 0x0001089c is .SUNW_version\n"
   "\t0x0001089c - 0x000108c0 is .rela.got\n"
   "\t0x000108c0 - 0x000108e4 is .rela.bss\n"
   "\t0x000108e4 - 0x00010998 is .rela.plt\n"
   "\t0x00010998 - 0x00010e74 is .text\n"
   "\t0x00010e74 - 0x00010e90 is .init\n"
   "\t0x00010e90 - 0x00010ea4 is .fini\n"
   "\t0x00010ea8 - 0x00010eeb is .rodata\n"
   "\t0x00010eec - 0x00010ef0 is 
.gnu.linkonce.r._ZNSt15basic_streambufIcSt11char_traitsIcEE13_S_pback_sizeE\n"
   "\t0x00020ef0 - 0x00020f18 is .got\n"
   "\t0x00020f18 - 0x00021000 is .plt\n"
   "\t0x00021000 - 0x000210e0 is .dynamic\n"
   "\t0x000210e0 - 0x000210ec"
2008.08.28 20:51:13
<- " is .data\n"
   "\t0x000210ec - 0x000210f8 is .ctors\n"
   "\t0x000210f8 - 0x00021104 is .dtors\n"
   "\t0x00021104 - 0x000211b0 is .eh_frame\n"
   "\t0x000211b0 - 0x000211b4 is .jcr\n"
   "\t0x000211b4 - 0x000211b8 is .data.rel.local\n"
   "\t0x000211b8 - 0x000211b9 is 
.gnu.linkonce.d._ZN16__Atomicity_lockILi0EE17_S_atomicity_lockE\n"
   "\t0x000211c0 - 0x00021300 is .bss\n"
   "(gdb) "
2008.08.28 20:51:13
-> "info program\n"
2008.08.28 20:51:13
<- "The program being debugged is not being run.\n"
   "(gdb) "
2008.08.28 20:51:13
-> "help detach\n"
2008.08.28 20:51:13
<- "Detach a process or file previously attached.\n"
   "If a process, it is no longer traced, and it continues its execution.  If\n"
   "you were debugging a file, the file is closed and gdb no longer accesses 
it.\n"
   "\n"
   "List of detach subcommands:\n"
   "\n"
   "\n"
   "Type \"help detach\" followed by detach subcommand name for full 
documentation.\n"
   "Type \"apropos word\" to search for commands related to \"word\".\n"
   "Command name abbreviations are allowed if unambiguous.\n"
   "(gdb) "
2008.08.28 20:51:13
-> "help run\n"
2008.08.28 20:51:13
<- "Start debugged program.  You may specify arguments to give it.\n"
   "Args may include \"*\", or \"[...]\"; they are expanded using \"sh\".\n"
   "Input and output redirection with \">\", \"<\", or \">>\" are also 
allowed.\n"
   "\n"
   "With no arguments, uses arguments last specified (with \"run\" or \"set 
args\").\n"
   "To cancel previous arguments and run with no arguments,\n"
   "use \"set args\" without arguments.\n"
   "(gdb) "
#  Starting GDB...done.
#  Welcome to DDD 3.3.11 "Rhubarb" (sparc-sun-solaris2.8)
2008.08.28 20:51:13
-> "help step\n"
2008.08.28 20:51:13
<- "Step program until it reaches a different source line.\n"
   "Argument N means do this N times (or till program stops for another 
reason).\n"
   "(gdb) "
2008.08.28 20:51:13
-> "help stepi\n"
2008.08.28 20:51:13
<- "Step one instruction exactly.\n"
   "Argument N means do this N times (or till program stops for another 
reason).\n"
   "(gdb) "
2008.08.28 20:51:13
-> "help next\n"
2008.08.28 20:51:13
<- "Step program, proceeding through subroutine calls.\n"
   "Like the \"step\" command as long as subroutine calls do not happen;\n"
   "when they do, the call is treated as one instruction.\n"
   "Argument N means do this N times (or till program stops for another 
reason).\n"
   "(gdb) "
2008.08.28 20:51:13
-> "help nexti\n"
2008.08.28 20:51:13
<- "Step one instruction, but proceed through subroutine calls.\n"
   "Argument N means do this N times (or till program stops for another 
reason).\n"
   "(gdb) "
2008.08.28 20:51:13
-> "help until\n"
2008.08.28 20:51:13
<- "Execute until the program reaches a source line greater than the current\n"
   "or a specified location (same args as break command) within the current 
frame.\n"
   "(gdb) "
2008.08.28 20:51:13
-> "help finish\n"
2008.08.28 20:51:13
<- "Execute until selected stack frame returns.\n"
   "Upon return, the value returned is printed and put in the value history.\n"
   "(gdb) "
2008.08.28 20:51:13
-> "help cont\n"
2008.08.28 20:51:13
<- "Continue program being debugged, after signal or breakpoint.\n"
   "If proceeding from breakpoint, a number N may be used as an argument,\n"
   "which means to set the ignore count of that breakpoint to N - 1 (so that\n"
   "the breakpoint won\'t break until the Nth time it is reached).\n"
   "(gdb) "
2008.08.28 20:51:13
-> "help signal\n"
2008.08.28 20:51:13
<- "Continue program giving it signal specified by the argument.\n"
   "An argument of \"0\" means continue program without giving it a signal.\n"
   "(gdb) "
2008.08.28 20:51:13
-> "help kill\n"
2008.08.28 20:51:13
<- "Kill execution of program being debugged.\n"
   "(gdb) "
2008.08.28 20:51:13
-> "help up\n"
2008.08.28 20:51:13
<- "Select and print stack frame that called this one.\n"
   "An argument says how many frames up to go.\n"
   "(gdb) "
2008.08.28 20:51:13
-> "help down\n"
2008.08.28 20:51:13
<- "Select and print stack frame called by this one.\n"
   "An argument says how many frames down to go.\n"
   "(gdb) "
2008.08.28 20:51:16
-> "set environment TERM dumb\n"
2008.08.28 20:51:16
<- "(gdb) "
2008.08.28 20:51:16
-> "run\n"
2008.08.28 20:51:16
<- "Find factors of what number? "
2008.08.28 20:51:18
-> "12\n"
2008.08.28 20:51:18
<- "Factors of n are: \n"
2008.08.28 20:51:22
<- "2 2 2  2 2 "
#  Saving options in "/home/sol-00/ehatteme/.ddd/init"...
#  Saving options in "/home/sol-00/ehatteme/.ddd/init"...done.
#  Saving history in "/home/sol-00/ehatteme/.ddd/history"...
#  Saving history in "/home/sol-00/ehatteme/.ddd/history"...done.
#  Thanks for using DDD 3.3.11!