Return the integer ID for the specified namespaceUri or -1 if the namespace has not been registered. Note that not all negative return values correspond to unregistered namespaces. Preregistered namespaces always have negative IDs. (See "Preregistered Namespaces" in the balxml_namespaceregistry component-level documentation.) Note that a return value of -1 can mean either an unregistered namespace or an empty URI string. This dual-use of -1 is deliberate and simplifies error handling in most clients.
Declared in <balxml_namespaceregistry.h>
int
lookup(std::string_view const& namespaceUri) const;