PRB: ShellExecuteEx Limits URL to MAX_PATH

This article was previously published under Q263909
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When you use the ShellExecute or ShellExecuteEx function on version 4.0 of the Shell32.dll file to open a URL, the URL is limited to (MAX_PATH - 1) characters. A URL should be able to be as long as (INTERNET_MAX_URL_LENGTH - 1) (defined in Wininet.h) characters.
ShellExecute and ShellExecuteEx copy the file string into an internal buffer. In the original version of Shell32.dll, the buffer's maximum size is MAX_PATH characters. Starting with Shell32.dll version 4.71, this internal buffer is expanded to INTERNET_MAX_URL_LENGTH characters.
This problem can be overcome by creating a temporary Internet shortcut file that contains the long URL and passing the Internet shortcut file to ShellExecute or ShellExecuteEx. After calling ShellExecute or ShellExecuteEx, this file can safely be deleted.

Code such as the following can be used to create an Internet shortcut file:
#include <windows.h>#include <shlobj.h>#include <intshcut.h>/**************************************************************************   CreateInternetShortcut()   pszShortcut - Path and file name of the Internet shortcut file. This    must have the URL extension for the shortcut to be used correctly.   pszURL - URL to be stored in the Internet shortcut file.   **************************************************************************/ HRESULT CreateInternetShortcut(LPTSTR pszShortcut, LPTSTR pszURL){IUniformResourceLocator *purl;HRESULT                 hr; hr = CoInitialize(NULL);if(SUCCEEDED(hr))    {    //Get a pointer to the IShellLink interface.    hr = CoCreateInstance(  CLSID_InternetShortcut,                            NULL,                            CLSCTX_INPROC_SERVER,                            IID_IUniformResourceLocator,                            (LPVOID*)&purl);       if(SUCCEEDED(hr))       {       IPersistFile* ppf;      hr = purl->QueryInterface(IID_IPersistFile, (LPVOID*)&ppf);      if(SUCCEEDED(hr))          {         hr = purl->SetURL(pszURL, 0);         if(SUCCEEDED(hr))            {            WCHAR wszShortcut[MAX_PATH];#ifdef UNICODE            lstrcpyn(wszShortcut, pszShortcut, MAX_PATH);#else            MultiByteToWideChar( CP_ACP,                                  0,                                  pszShortcut,                                  -1,                                  wszShortcut,                                  MAX_PATH); #endif            hr = ppf->Save(wszShortcut, FALSE);            }                    ppf->Release();          }              purl->Release();        }   CoUninitialize();   }return hr;}				
This behavior has been corrected in version 4.71 and later of Shell32.dll.

Article ID: 263909 - Last Review: 12/05/2015 20:25:53 - Revision: 1.2

  • Microsoft Platform Software Development Kit-January 2000 Edition
  • kbnosurvey kbarchive kbshellgrp kbprb KB263909