Question

With a static std::forward_list, the debugger only shows the 1’st element.

A non static std::forward_list or a static std::list works fine.

Is there any work around in the debugger I could use?

#include "stdafx.h"
#include <forward_list>
#include <list>

int _tmain(int argc, _TCHAR* argv[])
{
    static std::forward_list<int> sfl;
    sfl.push_front( 1 ); 
    sfl.push_front( 2 );

    std::forward_list<int> fl;
    fl.push_front( 1 ); 
    fl.push_front( 2 );

    static std::list<int> sl;
    sl.push_front( 1 ); 
    sl.push_front( 2 );

    //Break here.
    //In a debugger watch window:
    //  'sfl' only shows the '2' element
    //  'fl' & 'sl' shows all elements.
    return 0;
}

Answer 1

I believe this is a bug in Visual Studio’s debugger visualizer. The closest thing to a workaround I’ve come up with is to modify the forward_list entry in autoexp.dat (normally found in %VSINSTALLDIR%\Common7\Packages\Debugger\)

The file should have a section with the following:

;------------------------------------------------------------------------------
;  std::forward_list from <forward_list>
;------------------------------------------------------------------------------
std::forward_list<*>{
    preview (
        #(
            "(",
            #list(
                head: $e._Myhead,
                next: _Next
            ) : $e._Myval,
            ")"
        )
    )

    children (
        #list(
            head: $e._Myhead,
            next: _Next
        ) : $e._Myval
    )
}

Replace with:

;------------------------------------------------------------------------------
;  std::forward_list from <forward_list>
;------------------------------------------------------------------------------
std::forward_list<*>{
    preview (
        #(
            "(",
            #(
                $e._Myhead->_Myval,
                ",",
                #list(
                    head: $e._Myhead->_Next,
                    next: _Next
                ) : $e._Myval,
            ),
            ")"
        )
    )

    children (
        #(
            [actual 0]: $e._Myhead->_Myval,
            #list(
                head: $e._Myhead->_Next,
                next: _Next
            ) : $e._Myval
        )
    )
}

This is not a great solution. It displays the children as [actual 0], [0], [1], ... rather than [0], [1], [2], ..., i.e. element x is labelled [x-1].

You can however modify autoexp.dat without closing Visual Studio, you just need to restart the debugger. So I’d recommend using this hack for just as long as you need to debug a particular issue, and then revert back to the original autoexp.dat.