RPC_CONTROL(3NSL)RPC_CONTROL(3NSL)NAMErpc_control - library routine for manipulating global RPC attributes
for client and server applications
SYNOPSIS
bool_t rpc_control(int op, void *info);
DESCRIPTION
This RPC library routine allows applications to set and modify global
RPC attributes that apply to clients as well as servers. At present,
it supports only server side operations. This function allows applica‐
tions to set and modify global attributes that apply to client as well
as server functions. op indicates the type of operation, and info is a
pointer to the operation specific information. The supported values of
op and their argument types, and what they do are:
RPC_SVC_MTMODE_SET int * set multithread mode
RPC_SVC_MTMODE_GET int * get multithread mode
RPC_SVC_THRMAX_SET int * set maximum number of threads
RPC_SVC_THRMAX_GET int * get maximum number of threads
RPC_SVC_THRTOTAL_GET int * get number of active threads
RPC_SVC_THRCREATES_GET int * get number of threads created
RPC_SVC_THRERRORS_GET int * get number of thread create errors
RPC_SVC_USE_POLLFD int * set number of file descriptors to unlimited
RPC_SVC_CONNMAXREC_SET int * set non-blocking max rec size
RPC_SVC_CONNMAXREC_GET int * get non-blocking max rec size
There are three multithread (MT) modes. These are:
RPC_SVC_MT_NONE Single threaded mode (default)
RPC_SVC_MT_AUTO Automatic MT mode
RPC_SVC_MT_USER User MT mode
Unless the application sets the Automatic or User MT modes, it will
stay in the default (single threaded) mode. See the Network Interfaces
Programmer's Guide for the meanings of these modes and programming
examples. Once a mode is set, it cannot be changed.
By default, the maximum number of threads that the server will create
at any time is 16. This allows the service developer to put a bound on
thread resources consumed by a server. If a server needs to process
more than 16 client requests concurrently, the maximum number of
threads must be set to the desired number. This parameter may be set
at any time by the server.
Set and get operations will succeed even in modes where the operations
don't apply. For example, you can set the maximum number of threads in
any mode, even though it makes sense only for the Automatic MT mode.
All of the get operations except RPC_SVC_MTMODE_GET apply only to the
Automatic MT mode, so values returned in other modes may be undefined.
By default, RPC servers are limited to a maximum of 1024 file descrip‐
tors or connections due to limitations in the historical interfaces
svc_fdset(3NSL) and svc_getreqset(3NSL). Applications written to use
the preferred interfaces of svc_pollfd(3NSL) and svc_getreq_poll(3NSL)
can use an unlimited number of file descriptors. Setting info to point
to a non-zero integer and op to RPC_SVC_USE_POLLFD removes the limita‐
tion.
Connection oriented RPC transports read RPC requests in blocking mode
by default. Thus, they may be adversely affected by network delays and
broken clients. RPC_SVC_CONNMAXREC_SET enables non-blocking mode and
establishes the maximum record size (in bytes) for RPC requests; RPC
responses are not affected. Buffer space is allocated as needed up to
the specified maximum, starting at the maximum or RPC_MAXDATASIZE,
whichever is smaller.
The value established by RPC_SVC_CONNMAXREC_SET is used when a connec‐
tion is created, and it remains in effect for that connection until it
is closed. To change the value for existing connections on a per-con‐
nection basis, see svc_control(3NSL).
RPC_SVC_CONNMAXREC_GET retrieves the current maximum record size. A
zero value means that no maximum is in effect, and that the connections
are in blocking mode.
info is a pointer to an argument of type int. Non-connection RPC trans‐
ports ignore RPC_SVC_CONNMAXREC_SET and RPC_SVC_CONNMAXREC_GET.
RETURN VALUES
This routine returns TRUE if the operation was successful and returns‐
FALSE otherwise.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌───────────────┬─────────────────┐
│ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├───────────────┼─────────────────┤
│MT-Level │ MT-Safe │
└───────────────┴─────────────────┘
SEE ALSOrpcbind(1M), rpc(3NSL), rpc_svc_calls(3NSL), attributes(5)
Network Interfaces Programmer's Guide
Feb 24, 1999 RPC_CONTROL(3NSL)
