WSSetMessageHandler (C Function)

int WSSetMessageHandler(WSLINK link,WSMessageHandlerObject h)

installs the urgent message handler function referenced by h for for link.

Details

  • The urgent message handler function is called when WSTP receives an urgent message from the other end of the connection.
  • WSSetMessageHandler() returns 0 in the event of an error, and a nonzero value if the function succeeds.
  • Use WSError() to retrieve the error code if WSSetMessageHandler() fails.
  • WSMessageHandlerObject is a pointer to a function of the form void f(WSLINK link,int m1,int m2).
  • WSSetMessageHandler() is declared in the WSTP header file wstp.h.

Examples

Basic Examples  (1)

#include "wstp.h"


/* handle three common WSTP urgent messages */

void f(WSLINK lp, int msg, int arg)
{
    if(msg == WSInterruptMessage)
        { /* generate an interrupt menu */ }
    else if(msg == WSAbortMessage)
        { /* abort the current operation */ }
    else if(msg == WSTerminateMessage)
        { /* shutdown the program */ }

    /* ... */
}


int main(int argc, char **argv)
{
    WSENV env;
    WSLINK link;
    int error;

    env = WSInitialize((char *)0);
    if(env == (WSENV)0)
        { /* unable to initialize WSTP environment */ }

    link = WSOpenArgcArgv(env, argc, argv, &error);
    if(link == (WSLINK)0 || error != WSEOK)
        { /* unable to create link */ }

    if(! WSSetMessageHandler(link, (WSMessageHandlerObject)f)
        { /* unable to install message handler for link */ }

    /* ... */

    WSClose(link);
    WSDeinitialize(env);

    return 0;
}