Jump to content United States-English
HP.com Home Products and Services Support and Drivers Solutions How to Buy
» Contact HP
More options
HP.com home
HP-UX Reference > R


HP-UX 11i Version 3: February 2007

Technical documentation

» Feedback
Content starts here

 » Table of Contents

 » Index


rpc_control — library routine for manipulating global RPC attributes for client and server applications


bool_t rpc_control(int op, void *info);


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. 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 # 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_USER User MT mode RPC_SVC_MT_AUTO Automatic MT mode

Unless the application sets the Automatic or User MT modes, it will stay in the default (single-threaded) mode. 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 descriptors or connections due to limitations in the historical interfaces svc_fdset and svc_getreqset() (see respective manpages). Applications written to use the preferred interfaces of svc_pollfd and svc_getreq_poll() (see respective manpages) 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 limitation.

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. If the value pointed to by info is -1, then the maximum recoed size is set to RPC_MAXDATASIZE.

The value established by RPC_SVC_CONNMAXREC_SET is used when a connection is created, and it remains in effect for that connection until it is closed. To change the value for existing connections on a per-connection basis, see svc_control(3N).

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. Non-connection RPC transports ignore RPC_SVC_CONNMAXREC_SET and RPC_SVC_CONNMAXREC_GET.

info is a pointer to an argument of type int.


Thread Safe:


Cancel Safe:


Fork Safe:


Async-cancel Safe:


Async-signal Safe:


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 fork() and before exec(). These functions should not be called by a multithreaded application that supports asynchronous cancellation or asynchronous signals.


This routine returns TRUE if the operation was successful and returns FALSE otherwise.

Printable version
Privacy statement Using this site means you accept its terms Feedback to webmaster
© 1983-2007 Hewlett-Packard Development Company, L.P.