🚀 go-pugleaf

"Mike Collins" <its@TheBottomOfThePost> wrote in message
news:46f0344e@newsgroups.borland.com...

> However, i'm struggling to find a way to determine that
> required size of the lpTargetPath.

You have to allocate a buffer of an initial size and then call the function
in a loop, increasing the size when needed, until the buffer is eventually
large enough, or an error occurs.  For example:

    DWORD dwLen = 1024;
    LPTSTR lpBuffer = LocalAlloc(LPTR, dwLen);
    while( lpBuffer != NULL )
    {
        if( QueryDosDevice(NULL, lpBuffer, dwLen) )
        {
            // use lpBuffer as needed ...
            break;
        }

        if( GetLastError() != ERROR_INSUFFICIENT_BUFFER )
        {
            // as error occured...
            break;
        }

        dwLen += 1024;
        LPTSTR lpNewBuffer = LocalReAlloc(lpBuffer, dwLen, LPTR);
        if( lpNewBuffer == NULL )
        {
            // could not resize memory, original memory is still valid...
            break;
        }

        lpBuffer = lpNewBuffer;
    }

    if( lpBuffer )
        LocalFree(lpBuffer);

> However there seems to be no way to bet the size of the
> required buffer.

You have to increase the buffer by an arbitrary size of your own choosing.
The function will not tell you the size to use.

> Usually, in API's, the size parameter is modified if the buffer
> is too small

Not always.  There are a several API functions that don't.


Gambit