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Index for Section 3 |
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Alphabetical listing for X |
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xdr(3)
NAME
xdr, xdr_accepted_reply, xdr_array, xdr_authunix_parms, xdr_bool,
xdr_bytes, xdr_callhdr, xdr_callmsg, xdr_char, xdr_destroy, xdr_double,
xdr_enum, xdr_float, xdr_free, xdr_functions, xdr_getpos, xdr_hyper,
xdr_inline, xdr_int, xdr_long, xdr_longlong_t, xdrmem_create, xdr_opaque,
xdr_opaque_auth, xdr_pmap, xdr_pmaplist, xdr_pointer, xdrrec_create,
xdrrec_endofrecord, xdrrec_eof, xdrrec_skiprecord, xdr_reference,
xdr_rejected_reply, xdr_replymsg, xdr_setpos, xdr_short, xdrstdio_create,
xdr_string, xdr_u_char, xdr_u_hyper, xdr_u_int, 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
#include <rpc/xdr.h>
xdr_accepted_reply(xdrs, ar)
XDR *xdrs;
struct accepted_reply *ar;
Used for encoding RPC reply messages. This routine is useful for users
who wish to generate RPC-style messages without using the RPC package.
xdr_array(xdrs, arrp, sizep, maxsize, elsize, elproc)
XDR *xdrs;
char **arrp;
u_int *sizep, maxsize, elsize;
xdrproc_t elproc;
A filter primitive that translates between variable-length arrays and
their corresponding external representations. The arrp parameter 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 elsize parameter 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 (1) if it succeeds, zero (0) otherwise.
xdr_authunix_parms(xdrs, aupp)
XDR *xdrs;
struct authunix_parms *aupp;
Used for describing UNIX credentials. This routine is useful for users
who wish to generate these credentials without using the RPC
authentication package.
xdr_bool(xdrs, bp)
XDR *xdrs;
bool_t *bp;
A filter primitive that translates between Booleans (C integers) and
their external representations. When encoding data, this filter
produces values of either one (1) or zero (0). This routine returns
one (1) if it succeeds, zero (0) otherwise.
xdr_bytes(xdrs, sp, sizep, maxsize)
XDR *xdrs;
char **sp;
u_int *sizep, maxsize;
A filter primitive that translates between counted byte strings and
their external representations. The sp parameter 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 (1) if it succeeds, zero (0) otherwise.
void
xdr_callhdr(xdrs, chdr)
XDR *xdrs;
struct rpc_msg *chdr;
Used for describing RPC call header messages. This routine is useful
for users who wish to generate RPC-style messages without using the
RPC package.
xdr_callmsg(xdrs, cmsg)
XDR *xdrs;
struct rpc_msg *cmsg;
Used for describing RPC call messages. This routine is useful for
users who wish to generate RPC-style messages without using the RPC
package.
xdr_char(xdrs, cp)
XDR *xdrs;
char *cp;
A filter primitive that translates between C characters and their
external representations. This routine returns one (1) if it
succeeds, zero (0) 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().
void
xdr_destroy(xdrs)
XDR *xdrs;
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(xdrs, dp)
XDR *xdrs;
double *dp;
A filter primitive that translates between C double precision numbers
and their external representations. This routine returns one (1) if
it succeeds, zero (0) otherwise.
xdr_enum(xdrs, ep)
XDR *xdrs;
enum_t *ep;
A filter primitive that translates between C enums (actually integers)
and their external representations. This routine returns one (1) if
it succeeds, zero (0) otherwise.
xdr_float(xdrs, fp)
XDR *xdrs;
float *fp;
A filter primitive that translates between C floats and their external
representations. This routine returns one (1) if it succeeds, zero
(0) otherwise.
void
xdr_free(proc, objp)
xdrproc_t proc;
char *objp;
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).
u_int
xdr_getpos(xdrs)
XDR *xdrs;
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(xdrs, hp)
XDR *xdrs;
longlong_t *hp;
A filter primitive that translates between C long integers and their
external representations. (The typedef longlong_t is defined as long
in the <rpc/types.h> file, which is included from the <rpc/xdr.h>
file.) This routine will translate all 8 bytes of data to the XDR
stream. Note that this differentiates this routine from xdr_long in
that they both take a pointer to a long as an argument, while xdr_long
only translates 4 bytes of data to the XDR stream. This routine
returns one (1) if it succeeds, zero (0) otherwise.
The xdr_hyper routine is functionally equivalent to the xdr_longlong_t
routine.
See the following section that explains the differences between
xdr_long and xdr_hyper.
long *
xdr_inline(xdrs, len)
XDR *xdrs;
int len;
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(xdrs, ip)
XDR *xdrs;
int *ip;
A filter primitive that translates between C integers and their
external representations. This routine returns one (1) if it
succeeds, zero (0) otherwise.
xdr_long(xdrs, lp)
XDR *xdrs;
long *lp;
A filter primitive that translates between C long integers and their
external representations. This routine returns one (1) if it
succeeds, zero (0) otherwise.
Note that the lp argument must be the C language type long. The amount
of data encoded to the XDR stream is only 4 bytes (not the full 8
bytes of data represented by the C long type). This is because in the
context of XDR streams a long type is considered to be 4 bytes. When
data is encoded from the XDR stream, 4 bytes will be received from the
XDR stream; the xdr_long interface then sign extends the high order 4
bytes of the C long type.
Prior to serializing the data on the ENCODE side the xdr_long performs
a validity check to ensure that the value represents a valid 32-bit
signed number. This involves determining that the signed value is no
less than the most negative 32-bit signed quantity (which is the
hexadecimal value 0x80000000) and no greater than the most positive
32-bit signed quantity (which is the hexadecimal value 0x7fffffff).
If the value pointed to by the lp argument is not within this range
the xdr_long interface returns an error.
To translate the full 8 bytes of a C long, use the xdr_hyper
interface.
See the following section that explains the differences between
xdr_long and xdr_hyper.
xdr_longlong_t(xdrs, hp)
XDR *xdrs;
longlong_t *hp;
A filter primitive that translates between C long integers and their
external representations. (The typedef longlong_t is defined as long
in the <rpc/types.h> file, which is included from the <rpc/xdr.h>
file.) This routine will translate all 8 bytes of data to the XDR
stream. Note that this differentiates this routine from xdr_long in
that they both take a pointer to a long as an argument, while xdr_long
only translates 4 bytes of data to the XDR stream. This routine
returns one (1) if it succeeds, zero (0) otherwise.
The xdr_longlong_t routine is functionally equivalent to the xdr_hyper
routine.
See the following section that explains the differences between
xdr_long and xdr_hyper.
void
xdrmem_create(xdrs, addr, size, op)
XDR *xdrs;
char *addr;
u_int size;
enum xdr_op op;
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(xdrs, cp, cnt)
XDR *xdrs;
char *cp;
u_int cnt;
A filter primitive that translates between fixed size opaque data and
its external representation. The cp parameter is the address of the
opaque object, and cnt is its size in bytes. This routine returns one
(1) if it succeeds, zero (0) otherwise.
xdr_opaque_auth(xdrs, ap)
XDR *xdrs;
struct opaque_auth *ap;
Used for describing RPC authentication information messages. This
routine is useful for users who wish to generate RPC-style messages
without using the RPC package.
xdr_pmap(xdrs, regs)
XDR *xdrs;
struct pmap *regs;
Used for describing parameters to various portmap procedures,
externally. This routine is useful for users who wish to generate
these parameters without using the pmap interface.
xdr_pmaplist(xdrs, rp)
XDR *xdrs;
struct pmaplist **rp;
Used for describing a list of port mappings, externally. This routine
is useful for users who wish to generate these parameters without
using the pmap interface.
xdr_pointer(xdrs, objpp, objsize, xdrobj)
XDR *xdrs;
char **objpp;
u_int objsize;
xdrproc_t xdrobj;
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.
void
xdrrec_create(xdrs, sendsize, recvsize, handle, readit, writeit)
XDR *xdrs;
u_int sendsize, recvsize;
char *handle;
int (*readit) (), (*writeit) ();
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 (0) 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 (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,
except that handle is passed to the former routines as the first
parameter. The XDR stream's op field must be set by the caller. The
sendsize and recvsize parameters should be multiples of 4.
Warning: this XDR stream implements an intermediate record stream.
Therefore there are additional bytes in the stream to provide record
boundary information.
xdrrec_endofrecord(xdrs, sendnow)
XDR *xdrs;
int sendnow;
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 (1) if it succeeds, zero
(0) otherwise.
xdrrec_eof(xdrs)
XDR *xdrs;
int empty;
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 (1) if the stream has no more
input, zero (0) otherwise.
xdrrec_skiprecord(xdrs)
XDR *xdrs;
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 (1) if it succeeds, zero (0) otherwise.
xdr_reference(xdrs, pp, size, proc)
XDR *xdrs;
char **pp;
u_int size;
xdrproc_t proc;
A primitive that provides pointer chasing within structures. The pp
parameter 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 (1) if it succeeds, zero (0)
otherwise.
Warning: this routine does not understand NULL pointers. Use
xdr_pointer() instead.
xdr_rejected_reply(xdrs, rr)
XDR *xdrs;
struct rejected_reply *rr;
Used for describing RPC reply messages. This routine is useful for
users who want to generate RPC-style messages without using the RPC
package.
xdr_replymsg(xdrs, rmsg)
XDR *xdrs;
struct rpc_msg *rmsg;
Used for describing RPC reply messages. This routine is useful for
users who want to generate RPC-style messages without using the RPC
package.
xdr_setpos(xdrs, pos)
XDR *xdrs;
u_int pos;
A macro that invokes the set position routine associated with the XDR
stream xdrs. The pos parameter is a position value obtained from
xdr_getpos(). This routine returns one (1) if the XDR stream could be
repositioned, and zero (0) 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(xdrs, sp)
XDR *xdrs;
short *sp;
A filter primitive that translates between C short integers and their
external representations. This routine returns one (1) if it
succeeds, zero (0) otherwise.
void
xdrstdio_create(xdrs, file, op)
XDR *xdrs;
FILE *file;
enum xdr_op op;
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 op parameter 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() on the file stream, but never fclose().
xdr_string(xdrs, sp, maxsize)
XDR
*xdrs;
char **sp;
u_int maxsize;
A filter primitive that translates between C strings and their
corresponding external representations. Strings cannot be longer than
maxsize. The sp parameter is the address of the string's pointer.
While decoding if *sp is NULL , the necessary storage is allocated to
hold this null-terminated string and *sp is set to point to this. This
storage can be freed by using xdr_free(). This routine returns one (1)
if it succeeds, zero (0) otherwise.
xdr_u_char(xdrs, ucp)
XDR *xdrs;
unsigned char *ucp;
A filter primitive that translates between unsigned C characters and
their external representations. This routine returns one (1) if it
succeeds, zero (0) otherwise.
xdr_u_hyper(xdrs, uhp)
XDR *xdrs;
u_longlong_t *uhp;
A filter primitive that translates between C unsigned long integers
and their external representations. (The typedef u_longlong_t is
defined as unsigned long in the <rpc/types.h> file, which is included
from the <rpc/xdr.h> file.) This routine will translate all 8 bytes of
data to the XDR stream. Note that this differentiates this routine
from xdr_u_long in that they both take a pointer to an unsigned long
as an argument, while xdr_u_long only translates 4 bytes of data to
the XDR stream. This routine returns one (1) if it succeeds, zero (0)
otherwise.
The xdr_u_hyper routine is functionally equivalent to the
xdr_u_longlong_t routine.
See the following section that explains the differences between
xdr_long and xdr_hyper.
xdr_u_int(xdrs, up)
XDR *xdrs;
unsigned *up;
A filter primitive that translates between C unsigned integers and
their external representations. This routine returns one (1) if it
succeeds, zero (0) otherwise.
xdr_u_long(xdrs, ulp)
XDR *xdrs;
unsigned long *ulp;
A filter primitive that translates between C unsigned long integers
and their external representations. This routine returns one (1) if
it succeeds, zero (0) otherwise.
Prior to serializing the data on the ENCODE side the xdr_u_long
performs a validity check to insure that the value represents a valid
32-bit unsigned number. This involves determining that the unsigned
value is no greater than the largest 32-bit unsigned quantity (which
is the hexadecimal value 0xffffffff). If the value pointed to by the
ulp argument is not within this range, the xdr_u_long interface
returns an error.
For DECODE operations, the 32-bit unsigned value is sign extended into
the 64-bit unsigned long referred to by the ulp argument.
Note that this routine actually translates 4 bytes of the data to or
from the XDR stream. Refer to the description of xdr_long for a more
detailed explanation.
xdr_u_longlong_t(xdrs, uhp)
XDR *xdrs;
u_longlong_t *uhp;
A filter primitive that translates between C unsigned long integers
and their external representations. (The typedef u_longlong_t is
defined as unsigned long in the <rpc/types.h> file, which is included
from the <rpc/xdr.h> file.) This routine will translate all 8 bytes of
data to the XDR stream. Note that this differentiates this routine
from xdr_u_long in that they both take a pointer to an unsigned long
as an argument, while xdr_u_long only translates 4 bytes of data to
the XDR stream. This routine returns one (1) if it succeeds, zero (0)
otherwise.
The xdr_u_longlong routine is functionally equivalent to the
xdr_u_hyper routine.
See the following section that explains the differences between
xdr_long and xdr_hyper.
xdr_u_short(xdrs, usp)
XDR *xdrs;
unsigned short *usp;
A filter primitive that translates between C unsigned short integers
and their external representations. This routine returns one (1) if
it succeeds, zero (0) otherwise.
xdr_union(xdrs, dscmp, unp, choices, dfault)
XDR *xdrs;
int *dscmp;
char *unp;
struct xdr_discrim *choices;
bool_t (*defaultarm) (); /* may equal NULL */
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
choices parameter 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 any of the values, the
associated proc is called to translate the union. The end of the
xdr_discrim() structure array is denoted by a NULL pointer. If the
discriminant is not found in the choices array, then the defaultarm
procedure is called (if it is not NULL). Returns one (1) if it
succeeds, zero (0) otherwise.
xdr_vector(xdrs, arrp, size, elsize, elproc)
XDR *xdrs;
char *arrp;
u_int size, elsize;
xdrproc_t elproc;
A filter primitive that translates between fixed-length arrays and
their corresponding external representations. The arrp parameter is
the address of the array, while size is the element count of the
array. The elsize parameter 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 (1) if it succeeds, zero (0) otherwise.
xdr_void()
This routine always returns one (1). It may be passed to RPC routines
that require a function parameter, where nothing is to be done.
xdr_wrapstring(xdrs, sp)
XDR *xdrs;
char **sp;
A primitive that calls xdr_string(xdrs, sp,MAXUNSIGNED); where
MAXUNSIGNED is the maximum value of an unsigned integer. The
xdr_wrapstring() primitive 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. The sp parameter
is the address of the pointer to the string. While decoding if *sp is
NULL , the necessary storage is allocated to hold the null-terminated
string and *sp is set to point to this. This storage can be freed by
using xdr_free(). Returns one (1) if it succeeds, zero (0) otherwise.
Differences Between xdr_long and xdr_hyper Routines
On Tru64 UNIX platforms, the C programming language and the XDR routines
apply different conventions to the definitions of the long data type.
On Tru64 UNIX platforms, the C programming language applies the following
conventions for int and long data types:
__________________________
Data Type bits bytes
__________________________
int 32 4 bytes
long 64 8 bytes
__________________________
The XDR routines apply the following conventions:
__________________________
Data Type bits bytes
__________________________
int 32 4 bytes
long 32 4 bytes
hyper 64 8 bytes
__________________________
The xdr_long() and xdr_u_long() interfaces serialize 4 bytes of data. The
xdr_hyper() and xdr_u_hyper() serialize 8 bytes of data.
On Tru64 UNIX systems, the second argument to both xdr_long and xdr_hyper
must be either a pointer or of the C language type long (8 bytes). When
xdr_hyper is called with a parameter that points to a long all 8-bytes are
serialized. In contrast, when xdr_long is called with a parameter that
points to a long only the low order 4-bytes are serialized.
When calling xdr_long on the DECODE operation, the upper 4-bytes of the
long are sign extended in accordance with the high order bit of the lower
4-byte quantity. This is necessary to maintain the XDR convention of
xdr_long serializing 4-bytes.
If you want all 8-bytes to be serialized, use the xdr_hyper interface.
The xdr_longlong_t and the xdr_u_longlong_t perform the same function as
the xdr_hyper and the xdr_u_hyper interfaces respectively.
DESCRIPTION
These routines allow C programmers to describe arbitrary data structures in
a machine-independent fashion. Data for ONC remote procedure calls are
transmitted using these routines.
RELATED INFORMATION
Routines: rpc(3)