👤
Home Man
Search
Today's Posts
Register

Linux & Unix Commands - Search Man Pages
Man Page or Keyword Search:
Select Section of Man Page:
Select Man Page Repository:

Linux 2.6 - man page for xdr_wrapstring (linux section 3)

XDR(3)				    Linux Programmer's Manual				   XDR(3)

NAME
       xdr - library routines for external data representation

SYNOPSIS AND 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  rou-
       tines.

       The prototypes below are declared in <rpc/xdr.h> and make use of the following types:

	   typedef int bool_t;

	   typedef bool_t (*xdrproc_ti) (XDR *, void *,...);

       For the declaration of the XDR type, see <rpc/xdr.h>.

       bool_t xdr_array(XDR *xdrs, char **arrp, unsigned int *sizep,
			unsigned int maxsize, unsigned int elsize,
			xdrproc_t elproc);

	      A  filter primitive that translates between variable-length arrays and their corre-
	      sponding external representations.  The argument 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 argument 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.

       bool_t xdr_bool(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  or
	      zero.  This routine returns one if it succeeds, zero otherwise.

       bool_t xdr_bytes(XDR *xdrs, char **sp, unsigned int *sizep,
			unsigned int maxsize);

	      A  filter primitive that translates between counted byte strings and their external
	      representations.	The argument 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.

       bool_t xdr_char(XDR *xdrs, char *cp);

	      A filter primitive that translates between C characters and their  external  repre-
	      sentations.   This  routine  returns  one  if  it  succeeds, zero otherwise.  Note:
	      encoded characters are not packed, and occupy 4 bytes each.  For arrays of  charac-
	      ters, it is worthwhile to consider xdr_bytes(), xdr_opaque() or xdr_string().

       void xdr_destroy(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.

       bool_t xdr_double(XDR *xdrs, double *dp);

	      A  filter  primitive  that  translates between C double precision numbers and their
	      external representations.  This routine returns one if it succeeds, zero otherwise.

       bool_t xdr_enum(XDR *xdrs, enum_t *ep);

	      A filter primitive that translates between C enums (actually  integers)  and  their
	      external representations.  This routine returns one if it succeeds, zero otherwise.

       bool_t xdr_float(XDR *xdrs, float *fp);

	      A  filter primitive that translates between C floats and their external representa-
	      tions.  This routine returns one if it succeeds, zero otherwise.

       void xdr_free(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 (recur-
	      sively).

       unsigned int xdr_getpos(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.

       long *xdr_inline(XDR *xdrs, int len);

	      A macro that invokes the inline 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 (0) 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.

       bool_t xdr_int(XDR *xdrs, int *ip);

	      A filter primitive that translates between C integers and their external	represen-
	      tations.	This routine returns one if it succeeds, zero otherwise.

       bool_t xdr_long(XDR *xdrs, long *lp);

	      A  filter primitive that translates between C long integers and their external rep-
	      resentations.  This routine returns one if it succeeds, zero otherwise.

       void xdrmem_create(XDR *xdrs, char *addr, unsigned 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).

       bool_t xdr_opaque(XDR *xdrs, char *cp, unsigned int cnt);

	      A  filter primitive that translates between fixed size opaque data and its external
	      representation.  The argument cp is the address of the opaque object,  and  cnt  is
	      its size in bytes.  This routine returns one if it succeeds, zero otherwise.

       bool_t xdr_pointer(XDR *xdrs, char **objpp,
			  unsigned int objsize, xdrproc_t xdrobj);

	      Like  xdr_reference()  except  that it serializes NULL pointers, whereas xdr_refer-
	      ence() does not.	Thus, xdr_pointer() can represent recursive data structures, such
	      as binary trees or linked lists.

       void xdrrec_create(XDR *xdrs, unsigned int sendsize,
			  unsigned int recvsize, char *handle,
			  int (*readit) (char *, char *, int),
			  int (*writeit) (char *, char *, int));

	      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 argument.  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.

       bool_t xdrrec_endofrecord(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 nonzero.  This routine returns one if it  suc-
	      ceeds, zero otherwise.

       bool_t xdrrec_eof(XDR *xdrs);

	      This routine can be invoked only on streams created by xdrrec_create().  After con-
	      suming the rest of the current record in the stream, this routine  returns  one  if
	      the stream has no more input, zero otherwise.

       bool_t xdrrec_skiprecord(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 if it succeeds, zero other-
	      wise.

       bool_t xdr_reference(XDR *xdrs, char **pp, unsigned int size,
			    xdrproc_t proc);

	      A primitive that provides pointer chasing within structures.  The  argument  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(XDR *xdrs, unsigned int pos);

	      A macro that invokes the set position routine associated with the XDR stream  xdrs.
	      The  argument  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.

       bool_t xdr_short(XDR *xdrs, short *sp);

	      A filter primitive that translates between C short integers and their external rep-
	      resentations.  This routine returns one if it succeeds, zero otherwise.

       void xdrstdio_create(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 stdio stream file.  The argument op deter-
	      mines 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).

       bool_t xdr_string(XDR *xdrs, char **sp, unsigned int maxsize);

	      A filter primitive that translates between C strings and their corresponding exter-
	      nal 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.

       bool_t xdr_u_char(XDR *xdrs, unsigned char *ucp);

	      A filter primitive that translates between unsigned C characters and their external
	      representations.	This routine returns one if it succeeds, zero otherwise.

       bool_t xdr_u_int(XDR *xdrs, unsigned *up);

	      A  filter  primitive that translates between C unsigned integers and their external
	      representations.	This routine returns one if it succeeds, zero otherwise.

       bool_t xdr_u_long(XDR *xdrs, unsigned long *ulp);

	      A filter primitive that translates between  C  unsigned  long  integers  and  their
	      external representations.  This routine returns one if it succeeds, zero otherwise.

       bool_t xdr_u_short(XDR *xdrs, unsigned short *usp);

	      A  filter  primitive  that  translates  between C unsigned short integers and their
	      external representations.  This routine returns one if it succeeds, zero otherwise.

       bool_t xdr_union(XDR *xdrs, int *dscmp, char *unp,
			struct xdr_discrim *choices,
			xdrproc_t defaultarm);	   /* may equal NULL */

	      A filter primitive that translates between a discriminated C union and  its  corre-
	      sponding	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 argument 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.

       bool_t xdr_vector(XDR *xdrs, char *arrp, unsigned int size,
			 unsigned int elsize, xdrproc_t elproc);

	      A  filter  primitive  that  translates between fixed-length arrays and their corre-
	      sponding external representations.  The argument arrp is the address of the pointer
	      to the array, while size is the element count of the array.  The argument elsize is
	      the sizeof each of the array's elements, and elproc is an XDR  filter  that  trans-
	      lates  between the array elements' C form, and their external representation.  This
	      routine returns one if it succeeds, zero otherwise.

       bool_t xdr_void(void);

	      This routine always returns one.	It may be passed to RPC routines that  require	a
	      function argument, where nothing is to be done.

       bool_t xdr_wrapstring(XDR *xdrs, char **sp);

	      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 arguments, and xdr_string(),
	      one of the most frequently used primitives, requires three.  Returns one if it suc-
	      ceeds, zero otherwise.

SEE ALSO
       rpc(3)

       The following manuals:
	      eXternal Data Representation Standard: Protocol Specification
	      eXternal Data Representation: Sun Technical Notes
	      XDR:  External Data Representation Standard, RFC 1014, Sun Microsystems, Inc., USC-
	      ISI.

COLOPHON
       This page is part of release 3.55 of the Linux man-pages project.  A  description  of  the
       project,     and    information	  about    reporting	bugs,	 can	be    found    at
       http://www.kernel.org/doc/man-pages/.

					    2007-12-30					   XDR(3)


All times are GMT -4. The time now is 10:21 AM.

Unix & Linux Forums Content Copyrightę1993-2018. All Rights Reserved.
×
UNIX.COM Login
Username:
Password:  
Show Password





Not a Forum Member?
Forgot Password?