*v8::String::Utf8Value(args[0]-ToString()) does not return the string of node.js addon argument

Question

I've found that *v8::String::Utf8Value(args[0]->ToString()) returns the proper string on node 0.8.2 32-bit and does not return the proper string on node 0.8.8 64-bit. does anybody understand why? My node.js addon looks like this: ``` #define BUILDING_NODE_EXTENSION #include #define MAX_OUTPUT_BUF 80 extern "C" char *do_sqlsig(char *in); using namespace v8; Handle Sqlsig(const Arguments& args) { HandleScope scope; char *c_arg, *ret; if (args.Length() < 1) { ThrowException(Exception::TypeError(String::New("Wrong number of arguments"))); return scope.Close(Undefined()); } c_arg = *v8::String::Utf8Value(args[0]->ToString()); ret = c_arg; //do_sqlsig(c_arg); return scope.Close(String::New(ret)); } void Init(Handle

Accepted Answer

The string that the pointer returned from `*v8::String::Utf8Value(args[0]->ToString());` is point at is destroyed at the end of this line (when `Utf8Value` is destroyed). You create and destroy a `Utf8Value` object in one line. It is undefined behavior when dereferencing a dangling pointer, and why you are seeing different results on different versions.

Break it up into two lines and the string will be valid as long as your `Utf8Value` object is in scope.

```
v8::String::Utf8Value str(args[0]->ToString());
c_arg = *str;
```

*v8::String::Utf8Value(args[0]->ToString()) does not return the string of node.js addon argument

Solution

Problem