RPC -WR5441 Dokumentacja Pobierz pdf (Strona 8)

Page 8 Remote Procedure Call Programming Guide

then you would call callrpc() as

callrpc(hostname, PROGNUM, VERSNUM, PROCNUM,

xdr_simple, &simple ...);

where xdr_simple() is written as:

#include <rpc/rpc.h>

xdr_simple(xdrsp, simplep)

XDR *xdrsp;

struct simple *simplep;

{

if (!xdr_int(xdrsp, &simplep->a))

return (0);

if (!xdr_short(xdrsp, &simplep->b))

return (0);

return (1);

}

An XDR routine returns nonzero (true in the sense of C) if it completes successfully, and zero otherwise. A

complete description of XDR is in the XDR Protocol Speciﬁcation section of this manual, only few imple-

mentation examples are given here.

In addition to the built-in primitives, there are also the prefabricated building blocks:

xdr_array() xdr_bytes() xdr_reference()

xdr_vector() xdr_union() xdr_pointer()

xdr_string() xdr_opaque()

To send a variable array of integers, you might package them up as a structure like this

struct varintarr {

int *data;

int arrlnth;

} arr;

and make an RPC call such as

callrpc(hostname, PROGNUM, VERSNUM, PROCNUM,

xdr_varintarr, &arr...);

with xdr_varintarr() deﬁned as:

xdr_varintarr(xdrsp, arrp)

XDR *xdrsp;

struct varintarr *arrp;

{

return (xdr_array(xdrsp, &arrp->data, &arrp->arrlnth,

MAXLEN, sizeof(int), xdr_int));

}

This routine takes as parameters the XDR handle, a pointer to the array, a pointer to the size of the array,

the maximum allowable array size, the size of each array element, and an XDR routine for handling each

array element.

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RPC -WR5441 Dokumentacja Strona 8