xdr(3N) xdr(3N)NAME 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, xdr_opaque, xdr_pointer, xdr_reference, xdr_setpos, xdr_short, xdr_string, xdr_u_char, xdr_u_int, xdr_u_long, xdr_u_short, xdr_union, xdr_vector, xdr_void, xdr_wrapstring, xdrmem_create, xdrrec_create, xdrrec_endofrecord, xdrrec_eof, xdrrec_skiprecord, xdrstdio_create - provide library routines for external data representation SYNOPSIS xdr_array(xdrs, arrp, sizep, maxsize, elsize, e lproc) XDR *xdrs; char **arrp; u_int *sizep, maxsize, elsize; xdrproc_t elproc; xdr_bool(xdrs, bp) XDR *xdrs; bool_t *bp; xdr_bytes(xdrs, sp, sizep, maxsize) XDR *xdrs; char **sp; u_int *sizep, maxsize; xdr_char(xdrs, cp) XDR *xdrs; char *cp; void xdr_destroy(xdrs) XDR *xdrs; xdr_double(xdrs, dp) XDR *xdrs; double *dp; xdr_enum(xdrs, ep) XDR *xdrs; enum_t *ep; xdr_float(xdrs, fp) XDR *xdrs; float *fp; void xdr_free(proc, objp) xdrproc_t proc; char *objp; January 1992 1
xdr(3N) xdr(3N)u_int xdr_getpos(xdrs) XDR *xdrs; long *xdr_inline(xdrs, len) XDR *xdrs; int len; xdr_int(xdrs, ip) XDR *xdrs; int *ip; xdr_long(xdrs, lp) XDR *xdrs; long *lp; void xdrmem_create(xdrs, addr, size, op) XDR *xdrs; char *addr; u_int size; enum xdr_op op; xdr_opaque(xdrs, cp, cnt) XDR *xdrs; char *cp; u_int cnt; xdr_pointer(xdrs, objpp, objsize, xdrobj) XDR *xdrs; char **objpp; u_int objsize; xdrproc_t xdrobj; void xdrrec_create(xdrs, sendsize, recvsize, handle, readit, writeit) XDR *xdrs; u_int sendsize, recvsize; char *handle; int (*readit)(), (*writeit)(); xdrrec_endofrecord(xdrs, sendnow) XDR *xdrs; int sendnow; xdrrec_eof(xdrs) XDR *xdrs; int empty; xdrrec_skiprecord(xdrs) XDR *xdrs; xdr_reference(xdrs, pp, size, proc) XDR *xdrs; 2 January 1992
xdr(3N) xdr(3N)char **pp; u_int size; xdrproc_t proc; xdr_setpos(xdrs, pos) XDR *xdrs; u_int pos; xdr_short(xdrs, sp) XDR *xdrs; short *sp; void xdrstdio_create(xdrs, file, op) XDR *xdrs; FILE *file; enum xdr_op op; xdr_string(xdrs, sp, maxsize) XDR *xdrs; char **sp; u_int maxsize; xdr_u_char(xdrs, ucp) XDR *xdrs; unsigned char *ucp; xdr_u_int(xdrs, up) XDR *xdrs; unsigned *up; xdr_u_long(xdrs, ulp) XDR *xdrs; unsigned long *ulp; xdr_u_short(xdrs, usp) XDR *xdrs; unsigned short *usp; xdr_union(xdrs, dscmp, unp, choices, dfault) XDR *xdrs; int *dscmp; char *unp; struct xdr_discrim *choices; bool_t (*defaultarm)(); xdr_vector(xdrs, arrp, size, elsize, elproc) XDR *xdrs; char *arrp; u_int size, elsize; xdrproc_t elproc; January 1992 3
xdr(3N) xdr(3N)xdr_void() xdr_wrapstring(xdrs, sp) XDR *xdrs; char **sp; 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 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 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 1 if it succeeds, 0 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 1 or 0. This routine returns 1 if it succeeds, 0 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 1 if it succeeds, 0 otherwise. xdr_char() is a filter primitive that translates between C characters and their external representations. This routine returns 1 if it succeeds, 0 otherwise. Encoded characters are not packed, and occupy 4 bytes each. For arrays of characters, it is worthwhile to consider the use of 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 1 if it succeeds, 0 otherwise. 4 January 1992
xdr(3N) xdr(3N)xdr_enum() is a filter primitive that translates between C enum data types (actually integers) and their external representations. This routine returns 1 if it succeeds, 0 otherwise. xdr_float() is a filter primitive that translates between C float data types and their external representations. This routine returns 1 if it succeeds, 0 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. 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. This routine may return 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. xdr_int() is a filter primitive that translates between C integers and their external representations. This routine returns 1 if it succeeds, 0 otherwise. xdr_long() is a filter primitive that translates between C long integers and their external representations. This routine returns 1 if it succeeds, 0 otherwise. 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 1 if it succeeds, 0 otherwise. xdr_pointer() is a primitive that is similar to xdr_reference() except that xdr_pointer serializes null pointers. Thus, xdr_pointer() can represent recursive data structures, such as binary trees or linked lists. xdr_reference() is a primitive that supports pointer chasing within structures. The parameter pp is the address of the pointer; size is the sizeof the structure that *pp points January 1992 5
xdr(3N) xdr(3N)to; and proc is an XDR procedure that filters the structure between its C form and its external representation. This routine returns 1 if it succeeds, 0 otherwise. 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 1 if the XDR stream could be repositioned, and 0 otherwise. 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 1 if it succeeds, 0 otherwise. xdrstdio_create() 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). 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. The value of sp is the address of the string's pointer. This routine returns 1 if it succeeds, 0 otherwise. xdr_u_char() is a filter primitive that translates between unsigned C characters and their external representations. This routine returns 1 if it succeeds, 0 otherwise. xdr_u_int() is a filter primitive that translates between C unsigned integers and their external representations. This routine returns 1 if it succeeds, 0 otherwise. xdr_u_long() is a filter primitive that translates between C unsigned long integers and their external representations. This routine returns 1 if it succeeds, 0 otherwise. xdr_u_short() A filter primitive that translates between C unsigned short integers and their external representations. This routine returns 1 if it succeeds, 0 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 6 January 1992
xdr(3N) xdr(3N)enum_t. Next the union located at unp is translated. The parameter 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, 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, the defaultarm procedure, if it is not null, is called. This routine returns 1 if it succeeds, 0 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 is the element count of the array. The parameter 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 1 if it succeeds, 0 otherwise. xdr_void() always returns 1. You can pass it to RPC routines that require a function parameter, where nothing is to be done. xdr_wrapstring() is a primitive that makes this call: xdr_string(xdrs, sp, MAXUN.UNSIGNED); 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. This routine returns 1 if it succeeds, 0 otherwise. xdrmem_create() 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 value of op which can be XDR_ENCODE, XDR_DECODE, or XDR_FREE, determines the direction of the XDR stream. xdrrec_create() initializes the XDR stream object pointed to by xdrs. The stream's data is written to a buffer of size sendsize; a value of 0 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 value of 0. 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 January 1992 7
xdr(3N) xdr(3N)first parameter. The XDR stream's op field must be set by the caller. This XDR stream implements an intermediate record stream. Therefore there are additional bytes in the stream to provide record boundary information. xdrrec_endofrecord() 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 1 if it succeeds, zero otherwise. xdrrec_eof() can be invoked only on streams created by xdrrec_create(). After consuming the rest of the current record in the stream, this routine returns 1 if the stream has no more input, 0 otherwise. xdrrec_skiprecord() can be invoked only on streams created by xdrrec_create(). It tells the XDR implementation to discard the rest of the current record in the stream's input buffer. This routine returns 1 if it succeeds, 0 otherwise. SEE ALSO rpc(3N) A/UX Network Applications Programming 8 January 1992