Increase JVM heap size when calling it from C++

Question

I have a program that loads images and only works properly increasing heap.
java McVImg
gives me an Out of memory error.
java -Xmx120M McVImg
works fine.
If I want to call JVM from a C++ program using Java native interface,
How should I increase JVM heap ?
Thanks in advance. Ignasi Villagrasa.

Answer 1

I'm trying to do what you told me and it doesn't work.
I show the C++ code I'm using:
void JavaParam::LoadJVM()
     JavaVMInitArgs vm_args;
     JavaVMOption options[2];
jint res;
     vm_args.version = JNI_VERSION_1_2;
JNI_GetDefaultJavaVMInitArgs(&vm_args);
     if (res < 0)
fprintf(stderr, " Requested version is not supported\n");
          fputs ("Requested version is not supported\n",traza);
          fflush(traza);
exit(-1);
     //Establecemos classpath
     //Atencion el classpath ser� el jar
     //options[0].optionString = "-Djava.class.path=..";
     options[0].optionString = "-Djava.class.path=..\\mcjava.jar";
     options[1].optionString = "-Xmx120M";
     //Nuevos argumentos
vm_args.options=options;
     vm_args.nOptions = 2;
     vm_args.ignoreUnrecognized = JNI_FALSE;
     //Creamos Maquina Virtual Java
res = JNI_CreateJavaVM(&jvm,(void **)&env,&vm_args);
if (res < 0)
fprintf(stderr, "Can't create Java VM: %d\n",(int)res);
          fprintf(traza, "Can't create Java VM RES: %d \n",(int)res);
          fflush(traza);
exit(1);
     jvm_creada = 1;
Is that right ?
Thanks in advance. Ignasi Villagrasa.