NULL is OK, both for passing and for returning.
This parameter is a 'user_data', for callbacks; many bindings can pass NULL here.
This parameter is a 'destroy_data', for callbacks.
Generics and defining elements of containers and arrays.
Parameter for returning results. Default is transfer full.
The callback is valid until first called.
The callback is valid until the GDestroyNotify argument is called.
Free data container after the code is done.
Free data after the code is done.
Don't free data after the code is done.
Unstable interfaces are experimental or transitional. They are typically used to give outside developers early access to new or rapidly changing technology, or to provide an interim solution to a problem where a more general solution is anticipated. No claims are made about either source or binary compatibility from one minor release to the next. The Unstable interface level is a warning that these interfaces are subject to change without warning and should not be used in unbundled products. Given such caveats, customer impact need not be a factor when considering incompatible changes to an Unstable interface in a major or minor release. Nonetheless, when such changes are introduced, the changes should still be mentioned in the release notes for the affected release.