table of contents
RPC_CLNT_CALLS(3) | Library Functions Manual | RPC_CLNT_CALLS(3) |
NAME¶
rpc_clnt_calls
,
clnt_call
, clnt_freeres
,
clnt_geterr
, clnt_perrno
,
clnt_perror
, clnt_sperrno
,
clnt_sperror
, rpc_broadcast
,
rpc_broadcast_exp
, rpc_call
— library routines for client side calls
SYNOPSIS¶
#include
<rpc/rpc.h>
enum clnt_stat
clnt_call
(CLIENT
*clnt, const rpcproc_t
procnum, const xdrproc_t
inproc, const caddr_t
in, const xdrproc_t
outproc, caddr_t
out, const struct timeval
tout);
bool_t
clnt_freeres
(CLIENT
*clnt, const xdrproc_t
outproc, caddr_t
out);
void
clnt_geterr
(const
CLIENT * clnt, struct
rpc_err * errp);
void
clnt_perrno
(const
enum clnt_stat stat);
void
clnt_perror
(CLIENT
*clnt, const char
*s);
char *
clnt_sperrno
(const
enum clnt_stat stat);
char *
clnt_sperror
(CLIENT
*clnt, const char *
s);
enum clnt_stat
rpc_broadcast
(const rpcprog_t
prognum, const rpcvers_t versnum,
const rpcproc_t procnum, const
xdrproc_t inproc, const caddr_t in,
const xdrproc_t outproc, caddr_t
out, const resultproc_t eachresult,
const char *nettype);
enum clnt_stat
rpc_broadcast_exp
(const rpcprog_t
prognum, const rpcvers_t versnum,
const rpcproc_t procnum, const
xdrproc_t xargs, caddr_t argsp,
const xdrproc_t xresults, caddr_t
resultsp, const resultproc_t eachresult,
const int inittime, const int
waittime, const char * nettype);
enum clnt_stat
rpc_call
(const char *host,
const rpcprog_t prognum, const
rpcvers_t versnum, const rpcproc_t procnum,
const xdrproc_t inproc, const char
*in, const xdrproc_t outproc,
char *out, const char
*nettype);
DESCRIPTION¶
RPC library routines allow C language programs to make procedure calls on other machines across the network. First, the client calls a procedure to send a request to the server. Upon receipt of the request, the server calls a dispatch routine to perform the requested service, and then sends back a reply.
The
clnt_call
(),
rpc_call
(),
and
rpc_broadcast
()
routines handle the client side of the procedure call. The remaining
routines deal with error handling in the case of errors.
Some of the routines take a
CLIENT handle as one of the arguments. A
CLIENT handle can be created by an RPC creation
routine such as
clnt_create
()
(see rpc_clnt_create(3)).
These routines are safe for use in multithreaded applications. CLIENT handles can be shared between threads, however in this implementation requests by different threads are serialized (that is, the first request will receive its results before the second request is sent).
Routines¶
See rpc(3) for the definition of the CLIENT data structure.
clnt_call
()- A function macro that calls the remote procedure
procnum associated with the client handle,
clnt, which is obtained with an RPC client creation
routine such as
clnt_create
() (see rpc_clnt_create(3)). The inproc argument is the XDR function used to encode the procedure's arguments, and outproc is the XDR function used to decode the procedure's results; in is the address of the procedure's argument(s), and out is the address of where to place the result(s). The tout argument is the time allowed for results to be returned, which is overridden by a time-out set explicitly throughclnt_control
(), see rpc_clnt_create(3). If the remote call succeeds, the status returned isRPC_SUCCESS
, otherwise an appropriate status is returned. clnt_freeres
()- A function macro that frees any data allocated by the RPC/XDR system when it decoded the results of an RPC call. The out argument is the address of the results, and outproc is the XDR routine describing the results. This routine returns 1 if the results were successfully freed, and 0 otherwise.
clnt_geterr
()- A function macro that copies the error structure out of the client handle to the structure at address errp.
clnt_perrno
()- Print a message to standard error corresponding to the condition indicated
by stat. A newline is appended. Normally used after
a procedure call fails for a routine for which a client handle is not
needed, for instance
rpc_call
(). clnt_perror
()- Print a message to the standard error indicating why an RPC call failed;
clnt is the handle used to do the call. The message
is prepended with string s and a colon. A newline is
appended. Normally used after a remote procedure call fails for a routine
which requires a client handle, for instance
clnt_call
(). clnt_sperrno
()- Take the same arguments as
clnt_perrno
(), but instead of sending a message to the standard error indicating why an RPC call failed, return a pointer to a string which contains the message. Theclnt_sperrno
() function is normally used instead ofclnt_perrno
() when the program does not have a standard error (as a program running as a server quite likely does not), or if the programmer does not want the message to be output withprintf
() (see printf(3)), or if a message format different than that supported byclnt_perrno
() is to be used. Note: unlikeclnt_sperror
() andclnt_spcreateerror
() (see rpc_clnt_create(3)),clnt_sperrno
() does not return pointer to static data so the result will not get overwritten on each call. clnt_sperror
()- Like
clnt_perror
(), except that (likeclnt_sperrno
()) it returns a string instead of printing to standard error. However,clnt_sperror
() does not append a newline at the end of the message. Warning: returns pointer to a buffer that is overwritten on each call. rpc_broadcast
()- Like
rpc_call
(), except the call message is broadcast to all the connectionless transports specified by nettype. If nettype isNULL
, it defaults to "netpath". Each time it receives a response, this routine callseachresult
(), whose form is: bool_teachresult
(caddr_t out, const struct netbuf * addr, const struct netconfig * netconf) where out is the same as out passed torpc_broadcast
(), except that the remote procedure's output is decoded there; addr points to the address of the machine that sent the results, and netconf is the netconfig structure of the transport on which the remote server responded. Ifeachresult
() returns 0,rpc_broadcast
() waits for more replies; otherwise it returns with appropriate status. Warning: broadcast file descriptors are limited in size to the maximum transfer size of that transport. For Ethernet, this value is 1500 bytes. Therpc_broadcast
() function usesAUTH_SYS
credentials by default (see rpc_clnt_auth(3)). rpc_broadcast_exp
()- Like
rpc_broadcast
(), except that the initial timeout, inittime and the maximum timeout, waittime are specified in milliseconds. The inittime argument is the initial time thatrpc_broadcast_exp
() waits before resending the request. After the first resend, the re-transmission interval increases exponentially until it exceeds waittime. rpc_call
()- Call the remote procedure associated with prognum,
versnum, and procnum on the
machine, host. The inproc
argument is used to encode the procedure's arguments, and
outproc is used to decode the procedure's results;
in is the address of the procedure's argument(s),
and out is the address of where to place the
result(s). The nettype argument can be any of the
values listed on rpc(3). This routine returns
RPC_SUCCESS
if it succeeds, or an appropriate status is returned. Use theclnt_perrno
() routine to translate failure status into error messages. Warning:rpc_call
() uses the first available transport belonging to the class nettype, on which it can create a connection. You do not have control of timeouts or authentication using this routine.
AVAILABILITY¶
These functions are part of libtirpc.
SEE ALSO¶
May 7, 1993 | Linux 5.14.0-427.18.1.el9_4.x86_64 |