xdr_array, xdr_bool, xdr_bytes, xdr_char, xdr_destroy,
xdr_double,
xdr_enum, xdr_float, xdr_free, xdr_getpos, xdr_inline,
xdr_int, xdr_long,
xdrmem_create, xdr_opaque, xdr_pointer, xdrrec_create,
xdrrec_endofrecord, xdrrec_eof, xdrrec_skiprecord,
xdr_reference,
xdr_setpos, xdr_short, xdrstdio_create, xdr_string,
xdr_u_char,
xdr_u_int, xdr_u_long, xdr_u_short, xdr_union, xdr_vector,
xdr_void,
xdr_wrapstring - library routines for external data representation
#include <sys/types.h>
#include <rpc/xdr.h>
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);
long *
xdr_inline(XDR *xdrs, int len);
int
xdr_int(XDR *xdrs, int *ip);
int
xdr_long(XDR *xdrs, long *lp);
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 empty);
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);
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_int(XDR *xdrs, unsigned int *up);
int
xdr_u_long(XDR *xdrs, unsigned long *ulp);
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);
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() is 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 size of 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() is 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() is 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() is 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() is 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() is 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() is a filter primitive that translates between the
C enum type
(actually an integer) and its external representations.
This routine returns
one if it succeeds, zero otherwise.
xdr_float() is a filter primitive that translates between
the C float
type and its external representations. This routine returns
one if it
succeeds, zero otherwise.
xdr_free() is a 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() is 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_inline() is 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() is a filter primitive that translates between C
integers and
their external representations. This routine returns one if
it succeeds,
zero otherwise.
xdr_long() is a filter primitive that translates between C
long integers
and their external representations. This routine returns
one if it succeeds,
zero otherwise.
xdrmem_create() is a routine which 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() is 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() is like xdr_reference() execpt 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() is a routine which 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() and
write(), 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() is a routine which 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() is a routine which 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() is a routine which 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() is a primitive that provides pointer chasing
within
structures. The parameter pp is the address of the pointer;
size is the
size of 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() is 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() is a filter primitive that translates between C
short integers
and their external representations. This routine returns one if it
succeeds, zero otherwise.
xdrstdio_create() is a routine which 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() on
the file stream, but never fclose().
xdr_string() is 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() is a filter primitive that translates between
unsigned C
characters and their external representations. This routine
returns one
if it succeeds, zero otherwise.
xdr_u_int() is 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() is 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_short() is 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() is 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 struct
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 struct
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() is 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 size
of 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() is a routine which always returns one. It may be
passed to
RPC routines that require a function parameter, but where
nothing is to
be done.
xdr_wrapstring() is 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.
rpc(3)
eXternal Data Representation Standard: Protocol
Specification.
eXternal Data Representation: Sun Technical Notes.
Sun Microsystems, Inc., XDR: External Data Representation
Standard, RFC
1014, USC-ISI.
OpenBSD 3.6 February 16, 1988
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