MATLAB: How to get the full name of the folder when given a short name (8.3 name) in MATLAB R2019a on Windows

MATLAB

I have a short name and I like to get the full name so I can display it in a nice format on my GUI. How can I expand folders like 'C:\PROGRA~2\MIE74D~1'; to its readable format?

Best Answer

MATLAB has no built-in functionality for that. However, there are several Windows APIs you can use from MATLAB to get the fullname. One way could be ActiveX like shown below. This should work as long you do not hit the MAX_PATH length limitation on Windows:
name = 'C:\PROGRA~2\MIE74D~1';
fso = actxserver('Scripting.FileSystemObject');
if fso.FileExists(name)
  f = fso.GetFile(name);
elseif fso.FolderExists(name)
  f = fso.GetFolder(name);
end
app = actxserver('Shell.Application');
fullname = get(invoke(app.NameSpace(f.ParentFolder.Path),'ParseName',f.Name),'Path')
fso.release
app.release
Alternatively , if you have access to PowerShell you can use
name = 'C:\PROGRA~2\MIE74D~1';
[a,b] = system(sprintf('powershell.exe -Command "(Get-Item ''%s'').FullName"',name))
Or the Windows API function GetLongPathNameW
https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-getlongpathnamew
used through a MEX file (callled toFullPath.cpp)
#include "mex.h"
#include "windows.h"
#define MAX_SIZE 2000
void mexFunction(int nlhs, mxArray* plhs[], int nrhs, const mxArray* prhs[]) {
    wchar_t  lpszLongPath[MAX_SIZE];
    wchar_t *tmp;
    DWORD res;
    mwSize dim[] = {1,0};
      tmp = (wchar_t*) malloc(sizeof(wchar_t) * (mxGetNumberOfElements(prhs[0])+1) );
      if (tmp == NULL) {
          plhs[0] = mxCreateCharArray((mwSize)2,dim);
          return;
      }
      wcsncpy(tmp, (wchar_t*)mxGetData(prhs[0]), mxGetNumberOfElements(prhs[0]));
      tmp[mxGetNumberOfElements(prhs[0])] = L'\0';
      res = GetLongPathNameW(tmp, lpszLongPath, MAX_SIZE);
      free(tmp);
if ( res == 0){
        plhs[0] = mxCreateCharArray((mwSize)2,dim);
        return;
    }
      dim[1] = (mwSize)res;
      plhs[0] = mxCreateCharArray((mwSize)2,dim);    
      wcsncpy((wchar_t*)mxGetData(plhs[0]),&(lpszLongPath[0]),res);
  }
compiled with
mex toFullPath.cpp
and called through:
name = 'C:\PROGRA~2\MIE74D~1';
res = toFullPath(sprintf('\\\\?\\%s',name))
Note that a \\?\ was added in front of the path to indicate a long path for Windows to avoid the MAX_PATH length limitation as mentioned in the Microsoft documentation linked above. You would need to remove that prefix in the result afterwards.
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