uri:uri_is_global/1

Availability::- use_module(library(uri)).(can be autoloaded)

[semidet]uri_is_global(+URI)

True if URI has a scheme. The semantics is the same as the code below, but the implementation is more efficient as it does not need to parse the other components, nor needs to bind the scheme.

uri_is_global(URI) :-
        uri_components(URI, Components),
        uri_data(scheme, Components, Scheme),
        nonvar(Scheme).