establish a virtual circuit to a process with the given name


#include <sys/vc.h>
pid_t qnx_vc_name_attach( nid_t nid,
                          unsigned length,
                          char *name );


The qnx_vc_name_attach() function attempts to establish a network link, called a virtual circuit, between your process, on your local node, and a remote process that has registered name on the remote node nid. An initial buffer of size length bytes is allocated on both the local and remote node.

Once a virtual circuit is attached, the two programs may communicate using the kernel functions (for example, Send(), Receive(), and Reply()) as if they were on the same node.

See the qnx_vc_attach() function for more detail about virtual circuits. The qnx_vc_name_attach() function is simply a version of qnx_vc_attach() that allows you to attach a virtual circuit to a process on another node without knowing its process ID, as long as you know a name it has registered. Virtual circuits and their message buffers are always allocated (that is, not shared) when you use the qnx_vc_name_attach() function.

If you specify zero or your own node number for nid, a search for a process that has registered name is conducted locally. If a match is found, the process ID of the local process is returned, and no virtual circuit is created.


The virtual process ID (vid) on your local node upon success. On error, -1 is returned and errno is set.


See qnx_vc_attach().


#include <stdio.h>
#include <errno.h>
#include <sys/vc.h>
#include <sys/kernel.h>

nid_t    nid;
pid_t    vid;
char    msg[1000];

void main()
    nid = 2;

     *    set up a vc to some manager on node 2 that has
     *    registered the name "Resource", with an initial
     *    vid buffer size of 1000 bytes.
    if( ( vid = qnx_vc_name_attach( nid, 1000,
     "Resource" ) ) == -1 ) {
      printf( "qnx_vc_name_attach() failed: " );
      printf( "errno = %d\n", errno );

     *    send the manager 10 bytes, limit
     *    reply to 1000 bytes
    if( Send( vid, msg, msg, 10, 1000 ) == -1 ) {
      printf( "Send() on vid %d failed: ", vid );
      printf( "errno = %d\n", errno );
    qnx_vc_detach( vid );



Interrupt handler No
Signal handler Yes, but modifies errno
Thread Yes

See also:

Creceive(), Creceivemx(), errno, qnx_name_attach(), qnx_vc_attach(), qnx_vc_detach(), Receive(), Receivemx(), Reply(), Replymx(), Readmsg(), Readmsgmx(), Send(), Sendfd(), Sendfdmx(), Sendmx(), Trigger(), Writemsg(), Writemsgmx()