can't debug small program on eclipse helios cdt using mingw/gdb under windows, console freezes

Question

I've been trying to use Eclipse CDT to do some c++ examples, i can run them just fine with the run command, but whenever i try to Debug, the console window freezes up, I'm able to input, but the program doesn't continue.

When I debug, i get the following output on the console window (no breakpoints, but breaks on main because of default settings):

Hello, world
put your name: 15^running

The continue button is disabled and doesn't do anything when I input something and hit enter. The 15 is a random number, sometimes its 16, 20 etc.

If I run the program under eclipse I get the input prompt just fine:

Hello, world
put your name: test
Hello test

this is the code I try to debug:

#include <iostream>
#include <string>

int main() {
    std::cout << "Hello, world" << std::endl;
    std::string name;
    std::cout << "put your name: ";
    std::cin >> name;
    std::cout << "Hello " + name << std::endl;
    return 0;
}

My path var:
C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\system32\WBEM;C:\Program Files\Java\jdk1.6.0_14\bin;C:\MinGW\bin

Eclipse version: Helios Service Release 2
CDT version: 7.0.2
OS: windows xp
GDB version: GNU gdb (GDB) 7.2

How can I debug this small example under CDT, without issues?

Answer 1

15^running looks as a result record from gdb's Machine Interface. Normally it shouldn't appear in the Eclipse console.

I recommend trying a different Create Process Launcher. It can be changed in the following way:

1. In Main menu choose "Run" -> "Debug Configurations...".

2. In the opened "Debug Configurations" window shown below click "Select other..." opposite "Using GDB (DSF) Create Process Launcher".

   

3. In the opened "Select Preferred Launcher" window shown below check "Use configuration specific settings", select "Standard Create Process Launcher" in the list below and click OK.

   

4. Now go to the Debugger tab in the "Debug Configurations" window, select debugger, e.g. "MinGW gdb" and click Apply.

   

With the Standard Create Process Launcher I am able to debug your program although "put your name:" is printed only after I type something and hit Enter, because the output stream is not flushed.

Answer 2

Try having a look at this http://www.cprogramming.com/gdbtutorial.html and see if that helps. Like can you press CTRL-C to break?

Also Cannot enter input with gdb. Help! might be a pointer although related to apple.

Answer 3

the following is from the Eclipse website's FAQ:

http://wiki.eclipse.org/CDT/User/FAQ#Eclipse_console_does_not_show_output_on_Windows

Eclipse console does not show output on Windows In Eclipse CDT on Windows, standard output of the program being run or debugged is fully buffered, because it is not connected to a Windwos console, but to a pipe. See bug 173732 for more details. Either add fflush calls after every printf or add the following lines in the start of the main function:

setvbuf(stdout, NULL, _IONBF, 0);
setvbuf(stderr, NULL, _IONBF, 0);

Seems like an expected bug on windows.