HP-UX Reference (11i v3 07/02) - 3 Library Functions N-Z (vol 7)

x
xdr_create(3N) xdr_create(3N)
NAME
xdr_create, xdr_destroy, xdrmem_create, xdrrec_create, xdrstdio_create - library routines for external data
representation stream creation
SYNOPSIS
#include <rpc/xdr.h>
void xdr_destroy(XDR *
xdrs);
void xdrmem_create(XDR *
xdrs,
const caddr_t
addr,
const u_int
size,
const enum xdr_op
op);
void xdrrec_create(XDR *
xdrs,
const u_int
sendsz,
const u_int
recvsz,
const caddr_t
handle,
const int (*
readit)(
const void *
read_handle,
char *
buf,
const int
len),
const int (*
writeit)(
const void *
write_handle,
const char *
buf,
const int
len));
void xdrstdio_create(XDR *
xdrs,
FILE *
file,
const enum xdr_op
op);
DESCRIPTION
XDR library routines allow C programmers to describe arbitrary data structures in a machine-independent
fashion. Protocols such as remote procedure calls (RPC) use these routines to describe the format of the
data.
These routines deal with the creation of XDR streams. XDR streams have to be created before any data
can be translated into XDR format.
Routines
See rpc(3N) for the definition of the XDR, CLIENT, and SVCXPRT
data structures. Any buffers passed to
the XDR routines must be properly aligned. It is suggested either that malloc(3C) be used to allocate these
buffers or that the programmer insure that the buffer address is divisible evenly by four.
void xdr_destroy()
A macro that invokes the destroy routine associated with the XDR stream, xdrs. Private data struc-
tures associated with the stream are freed. Using xdrs after invoking xdr_destroy()
is
undefined.
void xdrmem_create()
This routine initializes the XDR stream object pointed to by xdrs. The stream’s data is written to or
read from a chunk of memory at location addr whose length is no less than size bytes long. The
parameter op determines the direction of the XDR stream. The value of op can be either
XDR_ENCODE , XDR_DECODE ,orXDR_FREE. In the case where the value of size exceeds
INT_MAX, xdrmem_create() resets size to INT_MAX.
void xdrrec_create()
This routine initializes the read-oriented XDR stream object pointed to by xdrs. The stream’s data is
written to a buffer of size sendsz; a value of 0 indicates the system should use a suitable default. The
stream’s data is read from a buffer of size recvsz; it too can be set to a suitable default by passing a 0
value. When a stream’s output buffer is full, writeit is called. Similarly, when a stream’s input buffer
is empty, readit is called. The behavior of these two routines is similar to the system calls read()
and write() (see read(2) and write(2), respectively), except that an appropriate handle
(read_handle or write_handle) is passed to the former routines as the first parameter instead of a file
descriptor. The XDR stream’s op field must be set by the caller.
HP-UX 11i Version 3: February 2007 − 1 − Hewlett-Packard Company 671