CryptEnumProviderTypes

The CryptEnumProviderTypes function is used to enumerate the types of providers supported on the machine.

#include <wincrypt.h>
BOOL WINAPI CryptEnumProviderTypes(
  DWORD dwIndex,        // in
  DWORD *pdwReserved,   // in
  DWORD dwFlags,        // in
  DWORD *pdwProvType,   // out
  LPTSTR pszTypeName,   // out
  DWORD *pcbTypeName    // in/out
);

Parameters

dwIndex: The index of the next provider type to be enumerated.
pdwReserved: This parameter is reserved for future use and must be NULL.
dwFlags: The flag values. This parameter is reserved for future use and should always be zero.
pdwProvType: The address of the DWORD value designating the enumerated provider type.
pszTypeName: Pointer to a buffer that receives the data from the enumerated provider type. This is a string including the terminating NULL character. There are provider types which may not have friendly names and in this case no name will be returned and the returned value pointed to by pcbTypeName will be 0.
This parameter can be NULL if you want to get the size of the name for memory allocation purposes. For more information, see the "Common In/Out Parameter Conventions" section at the beginning of this Reference.
pcbTypeName: Pointer to a variable that specifies the size, in bytes, of the buffer pointed to by the pszTypeName parameter. When the function returns, the variable pointed to by the pcbTypeName parameter contains the number of bytes stored in the buffer. This parameter can be NULL, only if pszTypeName is NULL. There are provider types which may not have friendly names and in this case no name will be returned and the returned value pointed to by pcbTypeName will be 0.
Note that when processing the data returned in the buffer, applications need to use the actual size of the data returned. The actual size may be slightly smaller than the size of the buffer specified on input. (On input, buffer sizes are usually specified large enough to insure that the largest possible output data will fit in the buffer.) On output, the variable pointed to by this parameter is updated to reflect the actual size of the data copied to the buffer.

Return Values

If the function succeeds, the return value is TRUE. If it fails, the return value is FALSE. To retrieve extended error information, use the GetLastError function.

The following table lists the error codes most commonly returned by the GetLastError function. The error codes prefaced by "NTE" are generated by the particular CSP you are using.

Error code	Description
ERROR_NO_MORE_ITEMS	There are no more items to enumerate.
ERROR_NOT_ENOUGH_MEMORY	The operating system ran out of memory.
NTE_BAD_FLAGS	dwFlags has an unrecognized value.
NTE_FAIL	Something was wrong with the type registration.

Remarks

CryptEnumProviderTypes is used to enumerate the provider types on a machine. Once this is done, the providers for a specific type may be enumerated by using CryptEnumProviders.

Example

long   i;
DWORD  dwErr;

// Loop through enumerating provider types.
for (i=0;;i++)
{
if (!CryptEnumProviderTypes(i, NULL, 0, &dwType, NULL, NULL))
   {if (ERROR_NO_MORE_ITEMS != (dwErr = GetLastError()))
       {printf("ERROR - CryptEnumProviderTypes : %X\n", dwErr);
       }
    break;
   }
printf ("Provider Type %d\n", dwType);
}

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