xdr_union(3)                        CLIX                        xdr_union(3)



  NAME

    xdr_union - Library function for external data representation

  LIBRARY

    Berkeley Software Distribution Library (libbsd.a)

  SYNOPSIS

    #include <sys/xdr.h>

    xdr_union(
      XDR *xdrs ,
      int *dscmp ,
      char *unp ,
      struct xdr_discrim *choices ,
      bool_t (*defaultarm)() );

  PARAMETERS

    xdrs         Specifies the address for the XDR handle.

    dscmp        Points to the discriminant, which is used to select the
                 element in the choices array.

    unp          Specifies the address of the union itself.

    choices      Specifies the address of the array of [discriminant, proc]
                 pairs, which allows selection of the appropriate filter
                 function, based on its specifies discriminant.

    defaultarm   If not NULL, this parameter specifies the address for a
                 default filter procedure to call if the specifies
                 discriminant is not in the choices array.

  DESCRIPTION

    The xdr_union() function allows C programmers to describe arbitrary data
    structures in a machine-independent fashion.  Data for remote procedure
    calls are transmitted using this function.

    The xdr_union() function 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 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 the associated value, the proc is
    called to translate the union.  The end of the xdr_discrim structure array
    is denoted by a function of value NULL.  If the discriminant is not found



  2/94 - Intergraph Corporation                                              1

  xdr_union(3)                        CLIX                        xdr_union(3)



    in the choices array, the (*defaultarm)() procedure is called (if it's not
    NULL).

  RETURN VALUES

    If successful, this function returns 1.  Otherwise, it returns 0.

  RELATED INFORMATION

    Functions:  xdr_bytes(3), xdr_getpos(3), xdr_pointer(3), xdrrec_create(3),
    xdr_array(3), xdr_destroy(3), xdr_free(3), xdr_inline(3),
    xdrmem_create(3), xdr_opaque(3), xdr_union(3), xdr_vector(3), xdr_void(3),
    authunix_create(3), clnt_pcreateerror(3), clnt_perrno(3), clnt_perror(3),
    clntraw_create(3), clnttcp_create(3), pmap_set(3), svc_getargs(3),
    svc_getreqset(3), svc_register(3), svcerr_auth(3), svctcp_create(3),
    xprt_register(3), clnt_broadcast(3), clnt_call(3), clnt_create(3),
    clnt_control(3), clnt_destroy(3), clnt_freeres(3), clnt_geterr(3),
    clnt_getmyaddr(3), registerrpc(3), svc_destroy(3), svc_getcaller(3),
    svc_run(3), svc_sendreply(3), xdr_accepted_reply(3),
    xdr_authunix_parms(3), xdr_callhdr(3), xdr_callmsg(3), xdr_opaque_auth(3),
    xdr_pmap(3), xdr_pmaplist(3), xdr_rejected_reply(3), xdr_replymsg(3)

    CLIX Programming Guide

    XDR: External Data Representation Standard, RFC1014, Sun Microsystems,
    Inc., USC-ISI




























  2                                              Intergraph Corporation - 2/94