+++ /dev/null
-.\" This page was taken from the 4.4BSD-Lite CDROM (BSD license)
-.\"
-.\" %%%LICENSE_START(BSD_ONELINE_CDROM)
-.\" This page was taken from the 4.4BSD-Lite CDROM (BSD license)
-.\" %%%LICENSE_END
-.\"
-.\" @(#)xdr.3n 2.2 88/08/03 4.0 RPCSRC; from 1.16 88/03/14 SMI
-.\"
-.\" 2007-12-30, mtk, Convert function prototypes to modern C syntax
-.\"
-.TH XDR 3 2007-12-30 "" "Linux Programmer's Manual"
-.SH NAME
-xdr \- library routines for external data representation
-.SH SYNOPSIS AND DESCRIPTION
-.LP
-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.
-
-The prototypes below are declared in
-.I <rpc/xdr.h>
-and make use of the following types:
-.in +4n
-.nf
-
-.BI "typedef int " bool_t ;
-
-.BI "typedef bool_t (*" xdrproc_t ") (XDR *, void *,...);"
-.fi
-.in
-.LP
-For the declaration of the
-.I XDR
-type, see
-.IR <rpc/xdr.h> .
-.LP
-.nf
-.BI "bool_t xdr_array(XDR *" xdrs ", char **" arrp ", unsigned int *" sizep ,
-.BI " unsigned int " maxsize ", unsigned int " elsize ,
-.BI " xdrproc_t " elproc );
-.fi
-.IP
-A filter primitive that translates between variable-length arrays
-and their corresponding external representations.
-The argument
-.I arrp
-is the address of the pointer to the array, while
-.I sizep
-is the address of the element count of the array;
-this element count cannot exceed
-.IR maxsize .
-The argument
-.I elsize
-is the
-.I sizeof
-each of the array's elements, and
-.I 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.
-.LP
-.nf
-.BI "bool_t xdr_bool(XDR *" xdrs ", bool_t *" bp );
-.fi
-.IP
-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.
-.LP
-.nf
-.BI "bool_t xdr_bytes(XDR *" xdrs ", char **" sp ", unsigned int *" sizep ,
-.BI " unsigned int " maxsize );
-.fi
-.IP
-A filter primitive that translates between counted byte
-strings and their external representations.
-The argument
-.I sp
-is the address of the string pointer.
-The length of the
-string is located at address
-.IR sizep ;
-strings cannot be longer than
-.IR maxsize .
-This routine returns one if it succeeds, zero otherwise.
-.LP
-.nf
-.BI "bool_t xdr_char(XDR *" xdrs ", char *" cp );
-.fi
-.IP
-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
-.BR xdr_bytes (),
-.BR xdr_opaque ()
-or
-.BR xdr_string ().
-.LP
-.nf
-.BI "void xdr_destroy(XDR *" xdrs );
-.fi
-.IP
-A macro that invokes the destroy routine associated with the XDR stream,
-.IR xdrs .
-Destruction usually involves freeing private data structures
-associated with the stream.
-Using
-.I xdrs
-after invoking
-.BR xdr_destroy ()
-is undefined.
-.LP
-.nf
-.BI "bool_t xdr_double(XDR *" xdrs ", double *" dp );
-.fi
-.IP
-A filter primitive that translates between C
-.I double
-precision numbers and their external representations.
-This routine returns one if it succeeds, zero otherwise.
-.LP
-.nf
-.BI "bool_t xdr_enum(XDR *" xdrs ", enum_t *" ep );
-.fi
-.IP
-A filter primitive that translates between C
-.IR enum s
-(actually integers) and their external representations.
-This routine returns one if it succeeds, zero otherwise.
-.LP
-.nf
-.BI "bool_t xdr_float(XDR *" xdrs ", float *" fp );
-.fi
-.IP
-A filter primitive that translates between C
-.IR float s
-and their external representations.
-This routine returns one if it succeeds, zero otherwise.
-.LP
-.nf
-.BI "void xdr_free(xdrproc_t " proc ", char *" objp );
-.fi
-.IP
-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
-.I not
-freed, but what it points to
-.I is
-freed (recursively).
-.LP
-.nf
-.BI "unsigned int xdr_getpos(XDR *" xdrs );
-.fi
-.IP
-A macro that invokes the get-position routine
-associated with the XDR stream,
-.IR 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.
-.LP
-.nf
-.BI "long *xdr_inline(XDR *" xdrs ", int " len );
-.fi
-.IP
-A macro that invokes the inline routine associated with the XDR stream,
-.IR xdrs .
-The routine returns a pointer
-to a contiguous piece of the stream's buffer;
-.I len
-is the byte length of the desired buffer.
-Note: pointer is cast to
-.IR "long\ *" .
-.IP
-Warning:
-.BR 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.
-.LP
-.nf
-.BI "bool_t xdr_int(XDR *" xdrs ", int *" ip );
-.fi
-.IP
-A filter primitive that translates between C integers
-and their external representations.
-This routine returns one if it succeeds, zero otherwise.
-.LP
-.nf
-.BI "bool_t xdr_long(XDR *" xdrs ", long *" lp );
-.fi
-.IP
-A filter primitive that translates between C
-.I long
-integers and their external representations.
-This routine returns one if it succeeds, zero otherwise.
-.LP
-.nf
-.BI "void xdrmem_create(XDR *" xdrs ", char *" addr ", unsigned int " size ,
-.BI " enum xdr_op " op );
-.fi
-.IP
-This routine initializes the XDR stream object pointed to by
-.IR xdrs .
-The stream's data is written to, or read from,
-a chunk of memory at location
-.I addr
-whose length is no more than
-.I size
-bytes long.
-The
-.I op
-determines the direction of the XDR stream (either
-.BR XDR_ENCODE ,
-.BR XDR_DECODE ,
-or
-.BR XDR_FREE ).
-.LP
-.nf
-.BI "bool_t xdr_opaque(XDR *" xdrs ", char *" cp ", unsigned int " cnt );
-.fi
-.IP
-A filter primitive that translates between fixed size opaque data
-and its external representation.
-The argument
-.I cp
-is the address of the opaque object, and
-.I cnt
-is its size in bytes.
-This routine returns one if it succeeds, zero otherwise.
-.LP
-.nf
-.BI "bool_t xdr_pointer(XDR *" xdrs ", char **" objpp ,
-.BI " unsigned int " objsize ", xdrproc_t " xdrobj );
-.fi
-.IP
-Like
-.BR xdr_reference ()
-except that it serializes null pointers, whereas
-.BR xdr_reference ()
-does not.
-Thus,
-.BR xdr_pointer ()
-can represent
-recursive data structures, such as binary trees or
-linked lists.
-.LP
-.nf
-.BI "void xdrrec_create(XDR *" xdrs ", unsigned int " sendsize ,
-.BI " unsigned int " recvsize ", char *" handle ,
-.BI " int (*" readit ") (char *, char *, int),"
-.BI " int (*" writeit ") (char *, char *, int));"
-.fi
-.IP
-This routine initializes the XDR stream object pointed to by
-.IR xdrs .
-The stream's data is written to a buffer of size
-.IR sendsize ;
-a value of zero indicates the system should use a suitable default.
-The stream's data is read from a buffer of size
-.IR recvsize ;
-it too can be set to a suitable default by passing a zero value.
-When a stream's output buffer is full,
-.I writeit
-is called.
-Similarly, when a stream's input buffer is empty,
-.I readit
-is called.
-The behavior of these two routines is similar to
-the system calls
-.BR read (2)
-and
-.BR write (2),
-except that
-.I handle
-is passed to the former routines as the first argument.
-Note: the XDR stream's
-.I op
-field must be set by the caller.
-.IP
-Warning: this XDR stream implements an intermediate record stream.
-Therefore there are additional bytes in the stream
-to provide record boundary information.
-.LP
-.nf
-.BI "bool_t xdrrec_endofrecord(XDR *" xdrs ", int " sendnow );
-.fi
-.IP
-This routine can be invoked only on streams created by
-.BR xdrrec_create ().
-The data in the output buffer is marked as a completed record,
-and the output buffer is optionally written out if
-.I sendnow
-is nonzero.
-This routine returns one if it succeeds, zero otherwise.
-.LP
-.nf
-.BI "bool_t xdrrec_eof(XDR *" xdrs );
-.fi
-.IP
-This routine can be invoked only on streams created by
-.BR 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.
-.LP
-.nf
-.BI "bool_t xdrrec_skiprecord(XDR *" xdrs );
-.fi
-.IP
-This routine can be invoked only on
-streams created by
-.BR 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.
-.LP
-.nf
-.BI "bool_t xdr_reference(XDR *" xdrs ", char **" pp ", unsigned int " size ,
-.BI " xdrproc_t " proc );
-.fi
-.IP
-A primitive that provides pointer chasing within structures.
-The argument
-.I pp
-is the address of the pointer;
-.I size
-is the
-.I sizeof
-the structure that
-.I *pp
-points to; and
-.I 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.
-.IP
-Warning: this routine does not understand null pointers.
-Use
-.BR xdr_pointer ()
-instead.
-.LP
-.nf
-.BI "xdr_setpos(XDR *" xdrs ", unsigned int " pos );
-.fi
-.IP
-A macro that invokes the set position routine associated with
-the XDR stream
-.IR xdrs .
-The argument
-.I pos
-is a position value obtained from
-.BR xdr_getpos ().
-This routine returns one if the XDR stream could be repositioned,
-and zero otherwise.
-.IP
-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.
-.LP
-.nf
-.BI "bool_t xdr_short(XDR *" xdrs ", short *" sp );
-.fi
-.IP
-A filter primitive that translates between C
-.I short
-integers and their external representations.
-This routine returns one if it succeeds, zero otherwise.
-.LP
-.nf
-.BI "void xdrstdio_create(XDR *" xdrs ", FILE *" file ", enum xdr_op " op );
-.fi
-.IP
-This routine initializes the XDR stream object pointed to by
-.IR xdrs .
-The XDR stream data is written to, or read from, the
-.I stdio
-stream
-.IR file .
-The argument
-.I op
-determines the direction of the XDR stream (either
-.BR XDR_ENCODE ,
-.BR XDR_DECODE ,
-or
-.BR XDR_FREE ).
-.IP
-Warning: the destroy routine associated with such XDR streams calls
-.BR fflush (3)
-on the
-.I file
-stream, but never
-.BR fclose (3).
-.LP
-.nf
-.BI "bool_t xdr_string(XDR *" xdrs ", char **" sp ", unsigned int " maxsize );
-.fi
-.IP
-A filter primitive that translates between C strings and
-their corresponding external representations.
-Strings cannot be longer than
-.IR maxsize .
-Note:
-.I sp
-is the address of the string's pointer.
-This routine returns one if it succeeds, zero otherwise.
-.LP
-.nf
-.BI "bool_t xdr_u_char(XDR *" xdrs ", unsigned char *" ucp );
-.fi
-.IP
-A filter primitive that translates between
-.I unsigned
-C characters and their external representations.
-This routine returns one if it succeeds, zero otherwise.
-.LP
-.nf
-.BI "bool_t xdr_u_int(XDR *" xdrs ", unsigned *" up );
-.fi
-.IP
-A filter primitive that translates between C
-.I unsigned
-integers and their external representations.
-This routine returns one if it succeeds, zero otherwise.
-.LP
-.nf
-.BI "bool_t xdr_u_long(XDR *" xdrs ", unsigned long *" ulp );
-.fi
-.IP
-A filter primitive that translates between C
-.I "unsigned long"
-integers and their external representations.
-This routine returns one if it succeeds, zero otherwise.
-.LP
-.nf
-.BI "bool_t xdr_u_short(XDR *" xdrs ", unsigned short *" usp );
-.fi
-.IP
-A filter primitive that translates between C
-.I "unsigned short"
-integers and their external representations.
-This routine returns one if it succeeds, zero otherwise.
-.LP
-.nf
-.BI "bool_t xdr_union(XDR *" xdrs ", int *" dscmp ", char *" unp ,
-.BI " struct xdr_discrim *" choices ,
-.BI " xdrproc_t " defaultarm "); /* may equal NULL */"
-.fi
-.IP
-A filter primitive that translates between a discriminated C
-.I union
-and its corresponding external representation.
-It first
-translates the discriminant of the union located at
-.IR dscmp .
-This discriminant is always an
-.IR enum_t .
-Next the union located at
-.I unp
-is translated.
-The argument
-.I choices
-is a pointer to an array of
-.BR xdr_discrim ()
-structures.
-Each structure contains an ordered pair of
-.RI [ value , proc ].
-If the union's discriminant is equal to the associated
-.IR value ,
-then the
-.I proc
-is called to translate the union.
-The end of the
-.BR xdr_discrim ()
-structure array is denoted by a routine of value NULL.
-If the discriminant is not found in the
-.I choices
-array, then the
-.I defaultarm
-procedure is called (if it is not NULL).
-Returns one if it succeeds, zero otherwise.
-.LP
-.nf
-.BI "bool_t xdr_vector(XDR *" xdrs ", char *" arrp ", unsigned int " size ,
-.BI " unsigned int " elsize ", xdrproc_t " elproc );
-.fi
-.IP
-A filter primitive that translates between fixed-length arrays
-and their corresponding external representations.
-The argument
-.I arrp
-is the address of the pointer to the array, while
-.I size
-is the element count of the array.
-The argument
-.I elsize
-is the
-.I sizeof
-each of the array's elements, and
-.I 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.
-.LP
-.nf
-.BI "bool_t xdr_void(void);"
-.fi
-.IP
-This routine always returns one.
-It may be passed to RPC routines that require a function argument,
-where nothing is to be done.
-.LP
-.nf
-.BI "bool_t xdr_wrapstring(XDR *" xdrs ", char **" sp );
-.fi
-.IP
-A primitive that calls
-.B "xdr_string(xdrs, sp,MAXUN.UNSIGNED );"
-where
-.B MAXUN.UNSIGNED
-is the maximum value of an unsigned integer.
-.BR xdr_wrapstring ()
-is handy because the RPC package passes a maximum of two XDR
-routines as arguments, and
-.BR xdr_string (),
-one of the most frequently used primitives, requires three.
-Returns one if it succeeds, zero otherwise.
-.SH SEE ALSO
-.BR rpc (3)
-.LP
-The following manuals:
-.RS
-eXternal Data Representation Standard: Protocol Specification
-.br
-eXternal Data Representation: Sun Technical Notes
-.br
-.IR "XDR: External Data Representation Standard" ,
-RFC\ 1014, Sun Microsystems, Inc.,
-USC-ISI.
-.RE
-.SH COLOPHON
-This page is part of release 3.79 of the Linux
-.I man-pages
-project.
-A description of the project,
-information about reporting bugs,
-and the latest version of this page,
-can be found at
-\%http://www.kernel.org/doc/man\-pages/.
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