RPC_CLNT_CALLS

Section: C Library Functions (3)
Page Index

BSD mandoc

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

In rpc/rpc.h Ft enum clnt_stat Fn 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 Ft bool_t Fn clnt_freeres CLIENT *clnt const xdrproc_t outproc caddr_t out Ft void Fn clnt_geterr const CLIENT * clnt struct rpc_err * errp Ft void Fn clnt_perrno const enum clnt_stat stat Ft void Fn clnt_perror CLIENT *clnt const char *s Ft char * Fn clnt_sperrno const enum clnt_stat stat Ft char * Fn clnt_sperror CLIENT *clnt const char * s Ft enum clnt_stat Fo rpc_broadcast Fa const rpcprog_t prognum const rpcvers_t versnum Fa const rpcproc_t procnum const xdrproc_t inproc Fa const caddr_t in const xdrproc_t outproc caddr_t out Fa const resultproc_t eachresult const char *nettype Fc Ft enum clnt_stat Fo rpc_broadcast_exp Fa const rpcprog_t prognum const rpcvers_t versnum Fa const rpcproc_t procnum const xdrproc_t xargs Fa caddr_t argsp const xdrproc_t xresults Fa caddr_t resultsp const resultproc_t eachresult Fa const int inittime const int waittime Fa const char * nettype Fc Ft enum clnt_stat Fo rpc_call Fa const char *host const rpcprog_t prognum Fa const rpcvers_t versnum const rpcproc_t procnum Fa const xdrproc_t inproc const char *in Fa const xdrproc_t outproc char *out const char *nettype Fc

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 Fn clnt_call , Fn rpc_call , and Fn 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 Vt CLIENT handle as one of the arguments. A Vt CLIENT handle can be created by an RPC creation routine such as Fn clnt_create (see rpc_clnt_create3).

These routines are safe for use in multithreaded applications. Vt 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 Vt CLIENT data structure.

Fn clnt_call: A function macro that calls the remote procedure Fa procnum associated with the client handle, Fa clnt , which is obtained with an RPC client creation routine such as Fn clnt_create (see rpc_clnt_create3). The Fa inproc argument is the XDR function used to encode the procedure's arguments, and Fa outproc is the XDR function used to decode the procedure's results; Fa in is the address of the procedure's argument(s), and Fa out is the address of where to place the result(s). The Fa tout argument is the time allowed for results to be returned, which is overridden by a time-out set explicitly through Fn clnt_control , see rpc_clnt_create3. If the remote call succeeds, the status returned is RPC_SUCCESS otherwise an appropriate status is returned.
Fn 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 Fa out argument is the address of the results, and Fa outproc is the XDR routine describing the results. This routine returns 1 if the results were successfully freed, and 0 otherwise.
Fn clnt_geterr: A function macro that copies the error structure out of the client handle to the structure at address Fa errp .
Fn clnt_perrno: Print a message to standard error corresponding to the condition indicated by Fa 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 Fn rpc_call .
Fn clnt_perror: Print a message to the standard error indicating why an RPC call failed; Fa clnt is the handle used to do the call. The message is prepended with string Fa 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 Fn clnt_call .
Fn clnt_sperrno: Take the same arguments as Fn 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. The Fn clnt_sperrno function is normally used instead of Fn clnt_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 with Fn printf (see printf(3)), or if a message format different than that supported by Fn clnt_perrno is to be used. Note: unlike Fn clnt_sperror and Fn clnt_spcreateerror (see rpc_clnt_create3), Fn clnt_sperrno does not return pointer to static data so the result will not get overwritten on each call.
Fn clnt_sperror: Like Fn clnt_perror , except that (like Fn clnt_sperrno ) it returns a string instead of printing to standard error. However, Fn 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.
Fn rpc_broadcast: Like Fn rpc_call , except the call message is broadcast to all the connectionless transports specified by Fa nettype . If Fa nettype is NULL it defaults to Qq netpath . Each time it receives a response, this routine calls Fn eachresult , whose form is: Ft bool_t Fn eachresult caddr_t out const struct netbuf * addr const struct netconfig * netconf where Fa out is the same as Fa out passed to Fn rpc_broadcast , except that the remote procedure's output is decoded there; Fa addr points to the address of the machine that sent the results, and Fa netconf is the netconfig structure of the transport on which the remote server responded. If Fn eachresult returns 0, Fn 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. The Fn rpc_broadcast function uses AUTH_SYS credentials by default (see rpc_clnt_auth3).
Fn rpc_broadcast_exp: Like Fn rpc_broadcast , except that the initial timeout, Fa inittime and the maximum timeout, Fa waittime are specified in milliseconds. The Fa inittime argument is the initial time that Fn rpc_broadcast_exp waits before resending the request. After the first resend, the re-transmission interval increases exponentially until it exceeds Fa waittime .
Fn rpc_call: Call the remote procedure associated with Fa prognum , Fa versnum , and Fa procnum on the machine, Fa host . The Fa inproc argument is used to encode the procedure's arguments, and Fa outproc is used to decode the procedure's results; Fa in is the address of the procedure's argument(s), and Fa out is the address of where to place the result(s). The Fa 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 the Fn clnt_perrno routine to translate failure status into error messages. Warning: Fn rpc_call uses the first available transport belonging to the class Fa 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.