BBC BASIC Programmers' Reference

by Jon Ripley, January 2008

If you want to read the name of the file or directory pointed to by a short cut (link) file you can use the routine listed below. FNShell_GetShortcut takes a full path to a short cut (link) file and returns a path to the linked file:

      DEF FNShell_GetShortcut(LinkFile$)
      LOCAL ole32%, clsid%, iidsl%, iidpf%, wsz%, psl%, ppf%, psl{}, ppf{}, path%

      DIM clsid% LOCAL 15, iidsl% LOCAL 15, iidpf% LOCAL 15, path% LOCAL 255
      DIM wsz% LOCAL 2*LEN(LinkFile$)+1
      DIM psl{QueryInterface%, AddRef%, Release%, GetPath%, GetIDList%, SetIDList%, \
      \       GetDescription%, SetDescription%, GetWorkingDirectory%, \
      \       SetWorkingDirectory%, GetArguments%, SetArguments%, \
      \       GetHotkey%, SetHotkey%, GetShowCmd%, SetShowCmd%, GetIconLocation%, \
      \       SetIconLocation%, SetRelativePath%, Resolve%, SetPath%}
      DIM ppf{QueryInterface%, AddRef%, Release%, GetClassID%, IsDirty%, \
      \       Load%, Save%, SaveCompleted%, GetCurFile%}

      SYS "LoadLibrary", "OLE32.DLL" TO ole32%
      SYS "GetProcAddress", ole32%, "CoInitialize" TO `CoInitialize`
      SYS "GetProcAddress", ole32%, "CoUninitialize" TO `CoUninitialize`
      SYS "GetProcAddress", ole32%, "CoCreateInstance" TO `CoCreateInstance`

      SYS `CoInitialize`, 0

      clsid%!0  = &00021401 : REM CLSID_ShellLink
      clsid%!4  = &00000000
      clsid%!8  = &000000C0
      clsid%!12 = &46000000

      iidsl%!0  = &000214EE : REM IID_IShellLink
      iidsl%!4  = &00000000
      iidsl%!8  = &000000C0
      iidsl%!12 = &46000000

      iidpf%!0  = &0000010B : REM IID_IPersistFile
      iidpf%!4  = &00000000
      iidpf%!8  = &000000C0
      iidpf%!12 = &46000000

      REM Get a pointer to the IShellLink interface:
      _CLSCTX_INPROC_SERVER = 1
      SYS `CoCreateInstance`, clsid%, 0, _CLSCTX_INPROC_SERVER, iidsl%, ^psl%
      IF psl% = 0 ERROR 100, "Cannot create IShellLink interface"
      !(^psl{}+4) = !psl%

      REM Query IShellLink for the IPersistFile interface:
      SYS psl.QueryInterface%, psl%, iidpf%, ^ppf%
      IF ppf% = 0 ERROR 100, "Cannot create IPersistFile interface"
      !(^ppf{}+4) = !ppf%

      REM Convert the path string to Unicode:
      SYS "MultiByteToWideChar", 0, 0, LinkFile$, -1, wsz%, LEN(LinkFile$)+1

      REM Load the link by calling IPersistFile::Load:
      SYS ppf.Load%, ppf%, wsz%, 0

      REM Get the target object:
      SYS psl.GetPath%, psl%, path%, 256, 0, 0

      REM Tidy up:
      SYS ppf.Release%, ppf%
      SYS psl.Release%, psl%
      SYS `CoUninitialize`
      =$$path%

For information about how to create a short cut see the article on creating a shortcut.