[#BloombergLP-balxml-NamespaceRegistry-lookup-05] = xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/balxml.adoc[balxml]::xref:BloombergLP/balxml/NamespaceRegistry.adoc[NamespaceRegistry]::lookup :relfileprefix: ../../../ :mrdocs: `lookup` overloads == Synopses Declared in `<balxml_namespaceregistry.h>` Return the null‐terminated string containing the URI of the namespace registered with the specified `id` or an empty (not null) string if `id` does not correspond to a preregistered namespace or a namespace that was previously registered with this object. [source,cpp,subs="verbatim,replacements,macros,-callouts"] ---- char const* xref:BloombergLP/balxml/NamespaceRegistry/lookup-00.adoc[lookup](int id) const; ---- [.small]#xref:BloombergLP/balxml/NamespaceRegistry/lookup-00.adoc[_» more..._]# 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. [source,cpp,subs="verbatim,replacements,macros,-callouts"] ---- int xref:BloombergLP/balxml/NamespaceRegistry/lookup-0c.adoc[lookup](std::string_view const& namespaceUri) const; ---- [.small]#xref:BloombergLP/balxml/NamespaceRegistry/lookup-0c.adoc[_» more..._]# [.small]#Created with https://www.mrdocs.com[MrDocs]#