get_value
Description:
Retrieves a value from a node and copies into value.
When done using it, call `g_value_unset()` on the `GValue` to free the associated resources.
It is a programmer error to call this on a node which doesn’t hold a scalar value. Use `JSON_NODE_HOLDS_VALUE` first.
Parameters:
| this |
a node |
| value |
return location for an uninitialized value |