.H A "Synopsis of XDR Routines"
.SH
xdr_array()
.LP
.LS
xdr_array(xdrs, arrp, sizep, maxsize, elsize, elproc)
	XDR *xdrs;
	char **arrp;
	u_int *sizep, maxsize, elsize;
	xdrproc_t elproc;
.LE
A filter primitive that translates between arrays
and their corresponding external representations.
The parameter
.L arrp
is the address of the pointer to the array, while
.L sizep
is the address of the element count of the array;
this element count cannot exceed
.L maxsize .
The parameter
.L elsize
is the
.L sizeof()
each of the array's elements, and
.L elproc
is an XDR filter that translates between
the array elements' C form, and their external representation.  
This routine returns one if it succeeds, zero otherwise.
.SH
xdr_bool()
.LP
.LS
xdr_bool(xdrs, bp)
	XDR *xdrs;
	bool_t *bp;
.LE
A filter primitive that translates between booleans (C integers)
and their external representations.
When encoding data, this filter produces values of either one or zero.
This routine returns one if it succeeds, zero otherwise.
.SH
xdr_bytes()
.LP
.LS
xdr_bytes(xdrs, sp, sizep, maxsize)
	XDR *xdrs;
	char **sp;
	u_int *sizep, maxsize;
.LE
A filter primitive that translates between counted byte strings
and their external representations.
The parameter
.L sp
is the address of the string pointer.
The length of the string is located at address
.L sizep ;
strings cannot be longer than
.L maxsize .
This routine returns one if it succeeds, zero otherwise.
.SH
xdr_destroy()
.LP
.LS
void
xdr_destroy(xdrs)
	XDR *xdrs;
.LE
A macro that invokes the destroy routine
associated with the XDR stream,
.L xdrs .
Destruction usually involves freeing private data structures
associated with the stream.  Using
.L xdrs
after invoking
.L xdr_destroy()
is undefined.
.SH
xdr_double()
.LP
.LS
xdr_double(xdrs, dp)
	XDR *xdrs;
	double *dp;
.LE
A filter primitive that translates between C
.L double
precision numbers and their external representations.
This routine returns one if it succeeds, zero otherwise.
.SH
xdr_enum()
.LP
.LS
xdr_enum(xdrs, ep)
	XDR *xdrs;
	enum_t *ep;
.LE
A filter primitive that translates between C
.L enum s
(actually integers) and their external representations.
This routine returns one if it succeeds, zero otherwise.
.SH
xdr_float()
.LP
.LS
xdr_float(xdrs, fp)
	XDR *xdrs;
	float *fp;
.LE
A filter primitive that translates between C
.L float s
and their external representations.
This routine returns one if it succeeds, zero otherwise.
.SH
xdr_getpos()
.LP
.LS
u_int
xdr_getpos(xdrs)
	XDR *xdrs;
.LE
A macro that invokes the get-position routine
associated with the XDR stream,
.L xdrs .
The routine returns an unsigned integer,
which indicates the position of the XDR byte stream.
A desirable feature of XDR streams
is that simple arithmetic works with this number,
although the XDR stream instances need not guarantee this.
.SH
xdr_inline()
.LP
.LS
long *
xdr_inline(xdrs, len)
	XDR *xdrs;
	int len;
.LE
A macro that invokes the in-line routine associated with the XDR stream,
.L xdrs .
The routine returns a pointer
to a contiguous piece of the stream's buffer;
.L len
is the byte length of the desired buffer.
Note that the pointer is cast to
.L "long *" .
Warning:
.L xdr_inline()
may return 0 (NULL) if it cannot allocate
a contiguous piece of a buffer.
Therefore the behavior may vary among stream instances;
it exists for the sake of efficiency.
.SH
xdr_int()
.LP
.LS
xdr_int(xdrs, ip)
	XDR *xdrs;
	int *ip;
.LE
A filter primitive that translates between C integers
and their external representations.
This routine returns one if it succeeds, zero otherwise.
.SH
xdr_long()
.LP
.LS
xdr_long(xdrs, lp)
	XDR *xdrs;
	long *lp;
.LE
A filter primitive that translates between C
.L long
integers and their external representations.
This routine returns one if it succeeds, zero otherwise.
.SH
xdr_opaque()
.LP
.LS
xdr_opaque(xdrs, cp, cnt)
	XDR *xdrs;
	char *cp;
	u_int cnt;
.LE
A filter primitive that translates between fixed size opaque data
and its external representation.
The parameter
.L cp
is the address of the opaque object, and
.L cnt
is its size in bytes.
This routine returns one if it succeeds, zero otherwise.
.SH
xdr_reference()
.LP
.LS
xdr_reference(xdrs, pp, size, proc)
	XDR *xdrs;
	char **pp;
	u_int size;
	xdrproc_t proc;
.LE
A primitive that provides pointer chasing within structures.
The parameter
.L pp
is the address of the pointer;
.L size
is the
.L sizeof()
the structure that
.L *pp
points to; and
.L proc
is an XDR procedure that filters the structure
between its C form and its external representation.
This routine returns one if it succeeds, zero otherwise.
.SH
xdr_setpos()
.LP
.LS
xdr_setpos(xdrs, pos)
	XDR *xdrs;
	u_int pos;
.LE
A macro that invokes the set position routine associated with the XDR stream
.L xdrs .
The parameter
.L pos
is a position value obtained from
.L xdr_getpos() .
This routine returns one if the XDR stream could be repositioned,
and zero otherwise.
Warning: it is difficult to reposition some types of XDR streams,
so this routine may fail with one type of stream and succeed with another. 
.SH
xdr_short()
.LP
.LS
xdr_short(xdrs, sp)
	XDR *xdrs;
	short *sp;
.LE
A filter primitive that translates between C
.L short
integers and their external representations.
This routine returns one if it succeeds, zero otherwise.
.SH
xdr_string()
.LP
.LS
xdr_string(xdrs, sp, maxsize)
	XDR *xdrs;
	char **sp;
	u_int maxsize;
.LE
A filter primitive that translates between C strings and their
corresponding external representations.
Strings cannot cannot be longer than
.L maxsize .
Note that
.L sp
is the address of the string's pointer.
This routine returns one if it succeeds, zero otherwise.
.SH
xdr_u_int()
.LP
.LS
xdr_u_int(xdrs, up)
	XDR *xdrs;
	unsigned *up;
.LE
A filter primitive that translates between C
.L unsigned
integers and their external representations.
This routine returns one if it succeeds, zero otherwise.
.SH
xdr_u_long()
.LP
.LS
xdr_u_long(xdrs, ulp)
	XDR *xdrs;
	unsigned long *ulp;
.LE
A filter primitive that translates between C
.L "unsigned long"
integers and their external representations.
This routine returns one if it succeeds, zero otherwise.
.SH
xdr_u_short()
.LP
.LS
xdr_u_short(xdrs, usp)
	XDR *xdrs;
	unsigned short *usp;
.LE
A filter primitive that translates between C
.L "unsigned short"
integers and their external representations.
This routine returns one if it succeeds, zero otherwise.
.SH
xdr_union()
.LP
.LS
xdr_union(xdrs, dscmp, unp, choices, dfault)
	XDR *xdrs;
	int *dscmp;
	char *unp;
	struct xdr_discrim *choices;
	xdrproc_t dfault;
.LE
A filter primitive that translates between a discriminated C
.L union
and its corresponding external representation.  The parameter 
.L dscmp
is the address of the union's discriminant, while
.L unp
in the address of the union.
This routine returns one if it succeeds, zero otherwise.
.SH
xdr_void()
.LP
.LS
xdr_void()
.LE
This routine always returns one.
It may be passed to RPC routines that require a function parameter,
where nothing is to be done.
.SH
xdr_wrapstring()
.LP
.LS
xdr_wrapstring(xdrs, sp)
	XDR *xdrs;
	char **sp;
.LE
A primitive that calls
.L xdr_string(xdrs,sp,MAXUNSIGNED);
where MAXUNSIGNED is the maximum value of an unsigned integer.
This is handy because the RPC package passes
only two parameters XDR routines, whereas
.L xdr_string() ,
one of the most frequently used primitives, requires three parameters.
This routine returns one if it succeeds, zero otherwise.
.SH
xdrmem_create()
.LP
.LS
void
xdrmem_create(xdrs, addr, size, op)
	XDR *xdrs;
	char *addr;
	u_int size;
	enum xdr_op op;
.LE
This routine initializes the XDR stream object pointed to by
.L xdrs .
The stream's data is written to, or read from,
a chunk of memory at location
.L addr
whose length is no more than
.L size
bytes long.  The
.L op
determines the direction of the XDR stream
(either XDR_ENCODE, XDR_DECODE, or XDR_FREE).
.SH
xdrrec_create()
.LP
.LS
void
xdrrec_create(xdrs, sendsize, recvsize, handle, readit, writeit)
	XDR *xdrs;
	u_int sendsize, recvsize;
	char *handle;
	int (*readit)(), (*writeit)();
.LE
This routine initializes the XDR stream object pointed to by
.L xdrs .
The stream's data is written to a buffer of size
.L sendsize ;
a value of zero indicates the system should use a suitable default.
The stream's data is read from a buffer of size
.L recvsize ;
it too can be set to a suitable default by passing a zero value.
When a stream's output buffer is full,
.L writeit()
is called.  Similarly, when a stream's input buffer is empty,
.L readit()
is called.  The behavior of these two routines
is similar to the UNIX system calls
.L read
and
.L write ,
except that
.L handle
is passed to the former routines as the first parameter.
Note that the XDR stream's
.L op
field must be set by the caller.
Warning: this XDR stream implements an intermediate record stream.
Therefore there are additional bytes in the stream
to provide record boundary information.
.SH
xdrrec_endofrecord()
.LP
.LS
xdrrec_endofrecord(xdrs, sendnow)
	XDR *xdrs;
	int sendnow;
.LE
This routine can be invoked only on streams created by
.L xdrrec_create() .
The data in the output buffer is marked as a completed record,
and the output buffer is optionally written out if
.L sendnow
is non-zero.  This routine returns one if it succeeds, zero otherwise.
.SH
xdrrec_eof()
.LP
.LS
xdrrec_eof(xdrs)
	XDR *xdrs;
	int empty;
.LE
This routine can be invoked only on streams created by
.L xdrrec_create() .
After consuming the rest of the current record in the stream,
this routine returns one if the stream has no more input, zero otherwise.
.SH
xdrrec_skiprecord()
.LP
.LS
xdrrec_skiprecord(xdrs)
	XDR *xdrs;
.LE
This routine can be invoked only on streams created by
.L xdrrec_create() .
It tells the XDR implementation that the rest of the current record
in the stream's input buffer should be discarded.
This routine returns one if it succeeds, zero otherwise.
.SH
xdrstdio_create()
.LP
.LS
void
xdrstdio_create(xdrs, file, op)
	XDR *xdrs;
	FILE *file;
	enum xdr_op op;
.LE
This routine initializes the XDR stream object pointed to by
.L xdrs .
The XDR stream data is written to, or read from, the Standard I/O stream
.L file .
The parameter
.L op
determines the direction of the XDR stream
(either XDR_ENCODE, XDR_DECODE, or XDR_FREE).
Warning: the destroy routine associated with such XDR streams calls
.L fflush()
on the
.L file
stream, but never
.L fclose() .