SymGetSymFromAddr64 works but SymGetLineFromAddr64 fails with error code 487 - c++

Question

I'm learning StackWalk API provided by "DbgHelp" in Windows 7. I wrote an exception filter that uses StackWalk64. The intention is to back trace at most 50 lines with function name and line number. "StackWalk64" iterates through each stack frame. The address(AddrPC) retrieved from Stack Frame is used in "SymGetSymFromAddr64" and "SymGetLineFromAddr64" to retrieve Symbol name and Line number respectively. But, though "SymGetSymFromAddr64" works successfully, "SymGetLineFromAddr64" fails. The Last Error returned is 487. How can the address work successfully for the former but not for the latter?
Am I missing something? Any Help?
LONG WINAPI TestStackWalker (EXCEPTION_POINTERS* lpFilter)
{
STACKFRAME64 st;
CONTEXT cc;
HANDLE hProcess = ::GetCurrentProcess();
HANDLE hThread = ::GetCurrentThread();
vector<IMAGEHLP_SYMBOL64> vectSymbs(50);
vector<IMAGEHLP_LINE64> vectLines(50);
if (!SymInitialize(hProcess, NULL, TRUE))
{
cout << "Issue with SymInitialize ! " << ::GetLastError() << endl;
return 1;
}
cc = *(lpFilter->ContextRecord);
printContext(cc);
::ZeroMemory(&st, sizeof(st));
st.AddrStack.Mode = AddrModeFlat;
st.AddrStack.Offset = cc.Esp;
st.AddrFrame.Mode = AddrModeFlat;
st.AddrFrame.Offset = cc.Ebp;
st.AddrPC.Mode = AddrModeFlat;
st.AddrPC.Offset = cc.Eip;
for (int i = 0; i < 50; i++)
{
if (!::StackWalk64(IMAGE_FILE_MACHINE_I386,
hProcess,
hThread,
&st,
&cc,
NULL,
SymFunctionTableAccess64,
SymGetModuleBase64,
NULL))
{
cout << "Issue with StackWalkFailed: " << ::GetLastError () <<endl;
return 1;
}
if (st.AddrReturn.Offset == st.AddrPC.Offset)
{
cout << "i think it's done!" << endl;
break;
}
if (st.AddrPC.Offset != 0)
{
vectSymbs[i].SizeOfStruct = sizeof(IMAGEHLP_SYMBOL64);
vectSymbs[i].MaxNameLength = 1024;
if (!SymGetSymFromAddr64 (hProcess, st.AddrPC.Offset, 0, &vectSymbs[i]))
{
cout << "Issue with Getting Symbol From Address " << ::GetLastError() << endl;
break;
}
SymSetOptions(SYMOPT_LOAD_LINES);
vectLines[i].SizeOfStruct = sizeof(IMAGEHLP_LINE64);
if (!SymGetLineFromAddr64 (hProcess, st.AddrPC.Offset, 0, &vectLines[i]))
{
cout << "Issue with Getting Line from Address " << ::GetLastError() << endl;
break;
}
cout << vectSymbs[i].Name << " at " << vectLines[i].LineNumber <<endl;
}
if (st.AddrReturn.Offset == 0)
{
cout << "seems finished " << endl;
break;
}
}
return 1;
}

Answer 1

The pdwDisplacement parameter is not optional:
DWORD dis;
if (!SymGetLineFromAddr64 (hProcess, st.AddrPC.Offset, &dis, &vectLines[i]))
{
cout << "Issue with Getting Line from Address " << ::GetLastError() << endl;
break;
}

Answer 2

I had the same problem. My symbols were on a symbol server. The solution was to put symsrv.dll (from the Windows SDK) next to dbghelp.dll, so it can be loaded. Everything worked after that. In practice, the solution was to distribute both dbghelp.dll and symsrv.dll with my application (together with dbgcore.dll and srcsrv.dll). See the Modules list in Visual Studio, to verify that both symsrv.dll and dbghelp.dll are being loaded from where you expect.
More info here:
https://learn.microsoft.com/en-us/windows/desktop/Debug/using-symsrv
(See "Installation" section)
https://learn.microsoft.com/en-us/windows/desktop/Debug/dbghelp-versions (regarding obtaining and distributing those dlls)