xdr_create(3N)

NAME
     xdr_create:   xdr_destroy, xdrmem_create, xdrrec_create, xdrstdio_create
     - library routines for external data representation stream creation

DESCRIPTION
     XDR library routines allow C programmers to describe arbitrary data
     structures in a machine-independent fashion.  Protocols such as remote
     procedure calls (RPC) use these routines to describe the format of the
     data.

     These routines deal with the creation of XDR streams.  XDR streams have
     to be created before any data can be translated into XDR format.

   Routines
     See rpc(3N) for the definition of the XDR, CLIENT, and SVCXPRT data
     structures.

     #include <rpc/xdr.h>

     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.

     void
     xdrmem_create(XDR *xdrs, const caddr_t addr,
          const u_int size, const 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).

     void
     xdrrec_create(XDR *xdrs, const u_int sendsz,
          const u_int recvsz, const caddr_t handle,
          const int (*readit)(const void *, char *, const int),
          const int (*writeit)(const void *, const char *, const int));

          This routine initializes the XDR stream object pointed to by xdrs.
          The stream's data is written to a buffer of size sendsz; a value of
          0 indicates the system should use a suitable default.  The stream's
          data is read from a buffer of size recvsz; it too can be set to a
          suitable default by passing a 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 [see read(2)
          and write(2), respectively], except that handle (CLIENT, or SVCXPRT)
          is passed to the former routines as the first parameter instead of a
          file descriptor.  Note:  the XDR stream's op field must be set by
          the caller.

          Note:  this XDR stream implements an intermediate record stream.
          Therefore there are additional bytes in the stream to provide record
          boundary information.

     void
     xdrstdio_create(XDR *xdrs, FILE *file, const 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 parameter op determines the direction of the XDR
          stream (either XDR_ENCODE, XDR_DECODE, or XDR_FREE).

          Note:  the destroy routine associated with such XDR streams calls
          fflush on the file stream, but never fclose [see fclose(3S)].

SEE ALSO
     fclose(3S), read(2), rpc(3N), write(2), xdr_admin(3N), xdr_complex(3N),
     xdr_simple(3N)