RasEnumAutodialAddressesA function (ras.h)

Article
02/09/2023

The RasEnumAutodialAddresses function returns a list of all addresses in the AutoDial mapping database.

Syntax

DWORD RasEnumAutodialAddressesA(
  [in, out] LPSTR   *lppRasAutodialAddresses,
  [in, out] LPDWORD lpdwcbRasAutodialAddresses,
  [out]     LPDWORD lpdwcRasAutodialAddresses
);

Parameters

[in, out] lppRasAutodialAddresses

Pointer to an array of string pointers, with additional space for the storage of the strings themselves at the end of the buffer.

On output, each string receives the name of an address in the AutoDial mapping database.

If lppAddresses is NULL on input, RasEnumAutodialAddresses sets the lpdwcbAddresses and lpdwcAddresses parameters to indicate the required size, in bytes, and the number of address entries in the database.

[in, out] lpdwcbRasAutodialAddresses

Pointer to a variable that, on input, contains the size, in bytes, of the buffer specified by the lpRasEnumAutodialAddressespAddresses parameter.

Note

To determine the required buffer size, call RasEnumAutodialAddresses with lppAddresses set to NULL. The variable pointed to by lpdwcbAddresses should be set to zero. The function will return the required buffer size in lpdwcbAddresses and an error code of ERROR_BUFFER_TOO_SMALL.

[out] lpdwcRasAutodialAddresses

Pointer to a variable that receives the number of address strings returned in the lppAddresses buffer.

Return value

If the function succeeds, the return value is ERROR_SUCCESS.

If the function fails, the return value is one of the following error codes or a value from Routing and Remote Access Error Codes or Winerror.h.

Value	Meaning
ERROR_INVALID_PARAMETER	NULL was passed for the lpdwcbAddresses or lpdwcAddresses parameter.
ERROR_BUFFER_TOO_SMALL	The lppAddresses buffer was NULL and lpdwcbAddresses was zero. The function returns the required buffer size in the variable pointed to by lpdwcbAddresses.

Remarks

The following code sample code uses RasEnumAutodialAddresses to enumerate the Autodial mapping database.

#include <windows.h>
#include <stdio.h>
#include "ras.h"
#include "raserror.h"
#include <tchar.h>

DWORD __cdecl wmain(){

    DWORD dwBytes = 0;
    DWORD dwRet = ERROR_SUCCESS;
    DWORD dwAddresses = 0;
    LPTSTR * lppAddresses = NULL;
    LPCTSTR lpEntryAddress = L"www.microsoft.com";

    // Allocate memory for a new Autodial address to add to the mapping database
    LPRASAUTODIALENTRY lpentry = (LPRASAUTODIALENTRY) HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, sizeof(RASAUTODIALENTRY));
    lpentry->dwSize = sizeof(RASAUTODIALENTRY);

    // Add a (non-functional) address to the Autodial mapping database
    // (this ensures RasEnumAutodialAddresses() has something to return)
    dwRet = RasSetAutodialAddress(lpEntryAddress, 0, lpentry, lpentry->dwSize, 1);
    
    // Call RasEnumAutodialAddresses() with lppAddresses = NULL. dwBytes is returned with the 
    // required buffer size and a return code of ERROR_BUFFER_TOO_SMALL
    dwRet = RasEnumAutodialAddresses(lppAddresses, &dwBytes, &dwAddresses);

    if (dwRet == ERROR_BUFFER_TOO_SMALL){
        // Allocate the memory needed for the array of RAS Autodial addresses.
        lppAddresses = (LPTSTR *) HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, dwBytes);
        if (lppAddresses == NULL){
            wprintf(L"HeapAlloc failed!\n");
            return 0;
        }
        
        // Call RasEnumAutodialAddresses() to enumerate all RAS Autodial addresses
        dwRet = RasEnumAutodialAddresses(lppAddresses, &dwBytes, &dwAddresses);

        // If successful, print the RAS Autodial addresses
        if (dwRet == ERROR_SUCCESS){
            wprintf(L"The following RAS Autodial addresses were found:\n");
            for (DWORD i = 0; i < dwAddresses; i++){
                wprintf(L"%s\n", lppAddresses[i]);
            }
        }
        // Remove the address
        dwRet = RasSetAutodialAddress(lpEntryAddress, 0, NULL, 0, 0);
        
        //Deallocate memory for the address buffers
        HeapFree(GetProcessHeap(), 0, lppAddresses);    
        HeapFree(GetProcessHeap(), 0, lpentry);
        lppAddresses = NULL;
        return 0;
    }

    // There was either a problem with RAS or there are no RAS Autodial addresses to enumerate
    if(dwAddresses >= 1){
        wprintf(L"The operation failed to acquire the buffer size.\n");
    }else{
        wprintf(L"There were no RAS Autodial addresses found.\n");
    }

    // Remove the address
    dwRet = RasSetAutodialAddress(lpEntryAddress, 0, NULL, 0, 0);
    HeapFree(GetProcessHeap(), 0, lpentry);
    return 0;
}

Note

The ras.h header defines RasEnumAutodialAddresses as an alias which automatically selects the ANSI or Unicode version of this function based on the definition of the UNICODE preprocessor constant. Mixing usage of the encoding-neutral alias with code that not encoding-neutral can lead to mismatches that result in compilation or runtime errors. For more information, see Conventions for Function Prototypes.

Requirements

Requirement	Value
Minimum supported client	Windows 2000 Professional [desktop apps only]
Minimum supported server	Windows 2000 Server [desktop apps only]
Target Platform	Windows
Header	ras.h
Library	Rasapi32.lib
DLL	Rasapi32.dll