A pathname inside the resource
A #GResourceLookupFlags
a location to place the length of the contents of the file, or null if the length is not needed
a location to place the flags about the file, or null if the length is not needed
true if the file was found. false if there were errors
Looks for a file at the specified path in the resource and if found returns information about it.
lookup_flags controls the behaviour of the lookup.