NAME
xdr,
xdr_array,
xdr_bool,
xdr_bytes,
xdr_char,
xdr_destroy,
xdr_double,
xdr_enum,
xdr_float,
xdr_free,
xdr_getpos,
xdr_hyper,
xdr_inline,
xdr_int,
xdr_long,
xdr_longlong_t,
xdrmem_create,
xdr_opaque,
xdr_pointer,
xdrrec_create,
xdrrec_endofrecord,
xdrrec_eof,
xdrrec_skiprecord,
xdr_reference,
xdr_setpos,
xdr_short,
xdr_sizeof,
xdrstdio_create,
xdr_string,
xdr_u_char,
xdr_u_hyper,
xdr_u_long,
xdr_u_longlong_t,
xdr_u_short,
xdr_union,
xdr_vector,
xdr_void,
xdr_wrapstring —
library routines for
external data representation
SYNOPSIS
int
xdr_array(
XDR
*xdrs,
char **arrp,
u_int *sizep,
u_int maxsize,
u_int elsize,
xdrproc_t elproc);
int
xdr_bool(
XDR
*xdrs,
bool_t *bp);
int
xdr_bytes(
XDR
*xdrs,
char **sp,
u_int *sizep,
u_int maxsize);
int
xdr_char(
XDR
*xdrs,
char *cp);
void
xdr_destroy(
XDR
*xdrs);
int
xdr_double(
XDR
*xdrs,
double *dp);
int
xdr_enum(
XDR
*xdrs,
enum_t *ep);
int
xdr_float(
XDR
*xdrs,
float *fp);
void
xdr_free(
xdrproc_t
proc,
char *objp);
u_int
xdr_getpos(
XDR
*xdrs);
int
xdr_hyper(
XDR
*xdrs,
longlong_t
*llp);
long *
xdr_inline(
XDR
*xdrs,
int len);
int
xdr_int(
XDR
*xdrs,
int *ip);
int
xdr_long(
XDR
*xdrs,
long *lp);
int
xdr_longlong_t(
XDR
*xdrs,
longlong_t
*llp);
void
xdrmem_create(
XDR
*xdrs,
char *addr,
u_int size,
enum xdr_op op);
int
xdr_opaque(
XDR
*xdrs,
char *cp,
u_int cnt);
int
xdr_pointer(
XDR
*xdrs,
char **objpp,
u_int objsize,
xdrproc_t xdrobj);
void
xdrrec_create(
XDR
*xdrs,
u_int
sendsize,
u_int
recvsize,
char
*handle,
int
(*readit)(),
int
(*writeit)());
int
xdrrec_endofrecord(
XDR
*xdrs,
int sendnow);
int
xdrrec_eof(
XDR
*xdrs);
int
xdrrec_skiprecord(
XDR
*xdrs);
int
xdr_reference(
XDR
*xdrs,
char **pp,
u_int size,
xdrproc_t proc);
int
xdr_setpos(
XDR
*xdrs,
u_int pos);
int
xdr_short(
XDR
*xdrs,
short *sp);
nsigned long
xdr_sizeof(
xdrproc_t
func,
void *data);
void
xdrstdio_create(
XDR
*xdrs,
FILE *file,
enum xdr_op op);
int
xdr_string(
XDR
*xdrs,
char **sp,
u_int maxsize);
int
xdr_u_char(
XDR
*xdrs,
unsigned char
*ucp);
int
xdr_u_hyper(
XDR
*xdrs,
u_longlong_t
*ullp);
int
xdr_u_int(
XDR
*xdrs,
unsigned *up);
int
xdr_u_long(
XDR
*xdrs,
unsigned long
*ulp);
int
xdr_u_longlong_t(
XDR
*xdrs,
u_longlong_t
*ullp);
int
xdr_u_short(
XDR
*xdrs,
unsigned short
*usp);
int
xdr_union(
XDR
*xdrs,
int *dscmp,
char *unp,
struct xdr_discrim
*choices,
bool_t
(*defaultarm)());
int
xdr_vector(
XDR
*xdrs,
char *arrp,
u_int size,
u_int elsize,
xdrproc_t elproc);
int
xdr_void(
void);
int
xdr_wrapstring(
XDR
*xdrs,
char **sp);
DESCRIPTION
These routines allow C programmers to describe arbitrary data structures in a
machine-independent fashion. Data for remote procedure calls are transmitted
using these routines.
-
-
- xdr_array()
- A filter primitive that translates between variable-length
arrays and their corresponding external representations. The parameter
arrp is the address of the pointer to the array,
while sizep is the address of the element count of
the array; this element count cannot exceed maxsize.
The parameter elsize is the sizeof
each of the array's elements, and 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.
-
-
- xdr_bool()
- 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.
-
-
- xdr_bytes()
- A filter primitive that translates between counted byte
strings and their external representations. The parameter
sp is the address of the string pointer. The length
of the string is located at address sizep; strings
cannot be longer than maxsize. This routine returns
one if it succeeds, zero otherwise.
-
-
- xdr_char()
- A filter primitive that translates between C characters and
their external representations. This routine returns one if it succeeds,
zero otherwise. Note: encoded characters are not packed, and occupy 4
bytes each. For arrays of characters, it is worthwhile to consider
xdr_bytes(), xdr_opaque() or
xdr_string().
-
-
- xdr_destroy()
- A macro that invokes the destroy routine associated with
the XDR stream, xdrs. Destruction usually involves
freeing private data structures associated with the stream. Using
xdrs after invoking xdr_destroy()
is undefined.
-
-
- xdr_double()
- A filter primitive that translates between C double
precision numbers and their external representations. This routine returns
one if it succeeds, zero otherwise.
-
-
- xdr_enum()
- A filter primitive that translates between C enums
(actually integers) and their external representations. This routine
returns one if it succeeds, zero otherwise.
-
-
- xdr_float()
- A filter primitive that translates between C floats and
their external representations. This routine returns one if it succeeds,
zero otherwise.
-
-
- xdr_free()
- Generic freeing routine. The first argument is the XDR
routine for the object being freed. The second argument is a pointer to
the object itself. Note: the pointer passed to this routine is
not freed, but what it points to is
freed (recursively).
-
-
- xdr_getpos()
- A macro that invokes the get-position routine associated
with the XDR stream, 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.
-
-
- xdr_hyper()
- A filter primitive that translates between ANSI C long long
integers and their external representations. This routine returns one if
it succeeds, zero otherwise.
-
-
- xdr_inline()
- A macro that invokes the in-line routine associated with
the XDR stream, xdrs. The routine returns a pointer
to a contiguous piece of the stream's buffer; len is
the byte length of the desired buffer. Note: pointer is cast to
long *.
Warning: xdr_inline() may return
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.
-
-
- xdr_int()
- A filter primitive that translates between C integers and
their external representations. This routine returns one if it succeeds,
zero otherwise.
-
-
- xdr_long()
- A filter primitive that translates between C long integers
and their external representations. This routine returns one if it
succeeds, zero otherwise.
-
-
- xdr_longlong_t()
- A filter primitive that translates between ANSI C long long
integers and their external representations. This routine returns one if
it succeeds, zero otherwise.
-
-
- 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 more than size bytes long. The
op determines the direction of the XDR stream
(either
XDR_ENCODE
,
XDR_DECODE
, or
XDR_FREE
).
-
-
- xdr_opaque()
- A filter primitive that translates between fixed size
opaque data and its external representation. The parameter
cp is the address of the opaque object, and
cnt is its size in bytes. This routine returns one
if it succeeds, zero otherwise.
-
-
- xdr_pointer()
- Like xdr_reference() except that it
serializes
NULL
pointers, whereas
xdr_reference() does not. Thus,
xdr_pointer() can represent recursive data structures,
such as binary trees or linked lists.
-
-
- xdrrec_create()
- This routine initializes the XDR stream object pointed to
by xdrs. The stream's data is written to a buffer of
size sendsize; a value of zero indicates the system
should use a suitable default. The stream's data is read from a buffer of
size recvsize; it too can be set to a suitable
default by passing a zero 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(2) and
write(2), except that
handle is passed to the former routines as the first
parameter. Note: the XDR stream's 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.
-
-
- xdrrec_endofrecord()
- This routine can be invoked only on streams created by
xdrrec_create(). The data in the output buffer is marked
as a completed record, and the output buffer is optionally written out if
sendnow is non-zero. This routine returns one if it
succeeds, zero otherwise.
-
-
- xdrrec_eof()
- This routine can be invoked only on streams created by
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.
-
-
- xdrrec_skiprecord()
- This routine can be invoked only on streams created by
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.
-
-
- xdr_reference()
- A primitive that provides pointer chasing within
structures. The parameter pp is the address of the
pointer; size is the sizeof the
structure that *pp points to; and
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.
Warning: this routine does not understand
NULL
pointers. Use xdr_pointer() instead.
-
-
- xdr_setpos()
- A macro that invokes the set position routine associated
with the XDR stream xdrs. The parameter
pos is a position value obtained from
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.
-
-
- xdr_short()
- A filter primitive that translates between C short integers
and their external representations. This routine returns one if it
succeeds, zero otherwise.
-
-
- xdr_sizeof()
- This routine returns the amount of memory required to
encode data using filter
func.
-
-
- xdrstdio_create()
- This routine initializes the XDR stream object pointed to
by xdrs. The XDR stream data is written to, or read
from, the Standard I/O stream file. The parameter
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
fflush(3) on the file
stream, but never
fclose(3).
-
-
- xdr_string()
- A filter primitive that translates between C strings and
their corresponding external representations. Strings cannot be longer
than maxsize. Note: sp is the
address of the string's pointer. This routine returns one if it succeeds,
zero otherwise.
-
-
- xdr_u_char()
- A filter primitive that translates between unsigned C
characters and their external representations. This routine returns one if
it succeeds, zero otherwise.
-
-
- xdr_u_hyper()
- A filter primitive that translates between unsigned ANSI C
long long integers and their external representations. This routine
returns one if it succeeds, zero otherwise.
-
-
- xdr_u_int()
- A filter primitive that translates between C unsigned
integers
and their external representations. This routine returns one if it
succeeds, zero otherwise.
-
-
- xdr_u_long()
- A filter primitive that translates between C unsigned long
integers and their external representations. This routine returns one if
it succeeds, zero otherwise.
-
-
- xdr_u_longlong_t()
- A filter primitive that translates between unsigned ANSI C
long long integers and their external representations. This routine
returns one if it succeeds, zero otherwise.
-
-
- xdr_u_short()
- A filter primitive that translates between C unsigned short
integers and their external representations. This routine returns one if
it succeeds, zero otherwise.
-
-
- xdr_union()
- A filter primitive that translates between a discriminated
C union and its corresponding external representation. It first translates
the discriminant of the union located at dscmp. This
discriminant is always an enum_t. Next the union located at
unp is translated. The parameter
choices is a pointer to an array of
xdr_discrim() structures. Each structure contains an
ordered pair of [value, proc].
If the union's discriminant is equal to the associated
value, then the proc is called
to translate the union. The end of the xdr_discrim()
structure array is denoted by a routine of value
NULL
. If the discriminant is not found in the
choices array, then the
defaultarm procedure is called (if it is not
NULL
). Returns one if it succeeds, zero
otherwise.
-
-
- xdr_vector()
- A filter primitive that translates between fixed-length
arrays and their corresponding external representations. The parameter
arrp is the address of the pointer to the array,
while size is the element count of the array. The
parameter elsize is the sizeof
each of the array's elements, and 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.
-
-
- xdr_void()
- This routine always returns one. It may be passed to RPC
routines that require a function parameter, where nothing is to be
done.
-
-
- xdr_wrapstring()
- A primitive that calls
xdr_string(xdrs,
sp, MAXUN.UNSIGNED); where
MAXUN.UNSIGNED
is the maximum value of an unsigned
integer. xdr_wrapstring() is handy because the RPC
package passes a maximum of two XDR routines as parameters, and
xdr_string(), one of the most frequently used
primitives, requires three. Returns one if it succeeds, zero
otherwise.
SEE ALSO
rpc(3)
The following manuals:
eXternal Data Representation Standard: Protocol
Specification.
eXternal Data Representation: Sun Technical
Notes.
Sun Microsystems, Inc., USC-ISI,
XDR: External Data Representation Standard,
RFC 1014, USC-ISI,
1014.