[#BloombergLP-bdlc-Queue-operator_subs-0d] = xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bdlc.adoc[bdlc]::xref:BloombergLP/bdlc/Queue.adoc[Queue]::operator[] :relfileprefix: ../../../ :mrdocs: Return a reference to the modifiable element at the specified `index` position in this queue. The reference will remain valid as long as this queue is not destroyed or modified (e.g., via `insert`, `remove`, or `append`). The behavior is undefined unless `0 <= index < length()`. == Synopsis Declared in `<bdlc_queue.h>` [source,cpp,subs="verbatim,replacements,macros,-callouts"] ---- T& operator[](int index); ---- [.small]#Created with https://www.mrdocs.com[MrDocs]#