xdr_admin(3N) xdr_admin(3N)
NAME
xdr_admin, xdr_control, xdr_getpos, xdr_inline, xdrrec_endofrecord, xdrrec_eof, xdrrec_readbytes, xdrrec_skiprecord, xdr_setpos, xdr_sizeof
- library routines for external data representation
SYNOPSIS
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 specifically with the management of the XDR stream.
Routines
See rpc(3N) for the definition of the data structure. Note that any buffers passed to the XDR routines must be properly aligned. It is
suggested either that malloc(3C) be used to allocate these buffers or that the programmer insure that the buffer address is divisible
evenly by four.
A function macro to change or retrieve various information
about an XDR stream. req indicates the type of operation and info is a pointer to the information. The supported value of req is
and its argument type is It returns the number of bytes left unconsumed in the stream and a flag indicating whether or not this is
the last fragment.
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. Therefore, applications written for portability should not depend on this feature.
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. Note: pointer is cast to
Warning: may return NULL 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, and applications written for portability should not depend on this feature.
This routine can be invoked only on streams created by
(see xdr_create(3N)). 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 if it succeeds, otherwise.
This routine can be invoked only on streams created by
After consuming the rest of the current record in the stream, this routine returns if there is no more data in the stream's input
buffer. It returns if there is additional data in the stream's input buffer.
This routine can be invoked only on streams created by
It attempts to read nbytes bytes from the XDR stream into the buffer pointed to by addr. Upon success this routine returns the num-
ber of bytes read, on failure. A return value of indicates an end of record.
This routine can be invoked only on streams created by
(see xdr_create(3N)). It tells the XDR implementation that the rest of the current record in the stream's input buffer should be
discarded. This routine returns if it succeeds, otherwise.
A macro that invokes the set position routine associated with the
XDR stream, xdrs. The parameter pos is a position value obtained from This routine returns if the XDR stream was repositioned, and
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. Therefore, applications written for portability should not depend on this feature.
This routine returns the number of bytes required to encode
data using the XDR filter function func, excluding potential overhead such as RPC headers or record markers. (zero) is returned on
error. This information might be used to select between transport protocols, or to determine the buffer size for various lower lev-
els of RPC client and server creation routines, or to allocate storage when XDR is used outside of the RPC subsystem.
MULTITHREAD USAGE
Thread Safe: Yes
Cancel Safe: Yes
Fork Safe: No
Async-cancel Safe: No
Async-signal Safe: No
These functions can be called safely in a multithreaded environment. They may be cancellation points in that they call functions that are
cancel points.
In a multithreaded environment, these functions are not safe to be called by a child process after and before These functions should not be
called by a multithreaded application that supports asynchronous cancellation or asynchronous signals.
SEE ALSO
malloc(3C), rpc(3N), xdr_complex(3N), xdr_create(3N), xdr_simple(3N).
xdr_admin(3N)