一个dll的调用，在c中可以实现，但在vb中怎样实现呢？主要是vb没有指针的概念，求助！！！

c中的调用：

char * FAPP, * FDWN;

FAPP = (char *)tpalloc("STRING", NULL, (long)9+1)
FDWN = (char *)tpalloc("STRING", NULL, (long)9+1)

if (tpinit((TPINIT *) NULL) == -1)
{
exit(1);
}

strcpy(FAPP, argv[1]);
strcat(FAPP, "0");
if(tpcall("UNLOADSTD",(char *)FAPP,0,(char **)&FDWN,&reclen,(long)0) == -1)
{
return ( -1 );
}


vb的调用：
Public Declare Function tpcall Lib "wtuxws32.dll" (ByVal SVCNAME$,
ByVal IDATA&, ByVal ILEN&, ODATA&, OLEN& ,
ByVal flags As Long)As Integer


怎样在vb中调用tpcall