#include <jni.h>
#include <stdio.h>
#include <signal.h>

// a very simple signal handler which, unless signal chaining is used
// will override JVMs signal handler
void mySigHandler( int sig ){
	printf("mySigHandler received signal: %d \n", sig );
	signal(SIGINT, mySigHandler);
}

/*
This example illusrates a possible problem of overriding JVM's signal handler.
*/

int main() {

    // create a JVM
    JNIEnv *env;
    JavaVM *jvm;
    jint res;
    

    JavaVMInitArgs vm_args;
    JavaVMOption options[1];
    options[0].optionString =
         "-Djava.class.path=/home/paul/jniSC/src/testJNI.jar";
    vm_args.version = JNI_VERSION_1_2;
    vm_args.options = options;
    vm_args.nOptions = 1;
    vm_args.ignoreUnrecognized = JNI_TRUE;
    /* Create the Java VM */
    res = JNI_CreateJavaVM(&jvm, (void**)&env, &vm_args);

    if (res < 0) {
       printf("Failed to create a JVM\n");
       return 1;
    } else {
	printf("successfully created JVM\n");
    }


    // when JVM is created and initialized.  Register a signal handler.   Unless signal chaining is used
    // this will override JVMs signal handler.   This will result in JVMs signal handler never being invoked.
    signal(SIGSEGV, mySigHandler);
    printf("Registered handler for SIGSEGV: %d \n", SIGSEGV );

    // find class jniProgressBar
    jclass cls = env->FindClass("jniProgressBar");
    if (cls == NULL) {
       printf("Failed to find a class jniProgressBar\n");
    } else {
	printf("succcessfully found a class jniProgressBar\n");
    }

    // find method id for addProgressBar method
    jmethodID addProgressBar = env->GetStaticMethodID( cls, "addProgressBar", "()V" );
    if( addProgressBar == 0 ){
	printf("failed to get addProgressBar method id\n");
	return 1;
    }

    // call Java addProgressBar method repeatedly
    while( 1 ){
	env->CallStaticVoidMethod( cls, addProgressBar );
	printf("in C++\n");
    }

    return 0;

}