cni converting String args[]

Fri Dec 10 16:43:00 GMT 2004

littlejohn@paranoici.org writes:
 > I'm quite lost finding a proper way to convert String[] args to a
 > char** array. The code I did is:
 > 
 > jint A::init(JArray< ::java::lang::String *> *args) {
 > 
 > int argc = 0;
 > char* arguments[argc];
 > 
 > if (args != NULL)
 > {
 > argc = args->length;
 > arguments[argc];
 > 
 > /*
 > * convert the JArray<String*>* in char**
 > */
 > ::java::lang::String** argsElements = elements(args);
 > //args[0];
 > 
 > for (int i = 0; i < argc; i++) {
 > //arguments[i] = (char *) JvGetStringChars(argsElements[i]);
 > arguments[i] = (char *) elements(argsElements[i]->getBytes());
If you want chars, you'll need an encoding -- elements returns a
jchar*. Try JvGetStringUTFRegion.
 > //arguments[i] = (char *) elements(argsElements[i]->toCharArray());
 > printf("%s\n ", arguments[i]);
 > }
 > }
 > return 0;
 > }
 > 
 > Aside this method does nothing but the conversion, I think I'm
 > misusing the elements function. On the first iteration the printf code
 > goes ok, on the second it writes garbage of gets a SIGSEGV, because
 > the argsElements[1] points to argsElement[0]+4 (I checked with gdb).
 > The commented out lines do not work either.
 > 
 > What am I missing?
I'm not exactly sure, but I wonder if something is being GCd under
your feet. Is everything here called from Java code, or do you have a
pointer to a Java type stashed in native code somewhere?
Andrew.