* The optional literal or variable [[INTEGER]] {{Parameter|start%}} indicates where in the {{Parameter|baseString$}} the search must start, counted from the left.
* The {{Parameter|baseString$}} is a literal or variable [[STRING]] value to be searched for an exact match including [[UCASE$|letter cases]].
* The {{Parameter|subString$}} is a literal or variable [[STRING]] value being searched.
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* The function returns the {{Parameter|position%}} in the {{Parameter|baseString$}} where the {{Parameter|subString$}} was found, from right to left.
* {{Parameter|position%}} will be 0 if the search found no matches in the base string.
* [[_INSTRREV]] returns 0 if an empty {{Parameter|baseString$}} is passed, and returns [[LEN]]({{Parameter|baseString$}}) with an empty {{Parameter|subString$}}.
* The {{Parameter|start%}} position is useful when making multiple searches in the same string. See the example below.
* The {{Parameter|subString$}} should be smaller or equal in [[LEN|length]] to the {{Parameter|baseString$}}, or 0 is returned.
* A {{Parameter|start%}} value of 0 or less starts search from the end of the {{Parameter|baseString$}} (same as not passing a {{Parameter|start%}} parameter).
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''Example 1:'' Separating a file name from a full path.
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fullPath$ = "C:\Documents and Settings\Administrator\Desktop\qb64\internal\c\libqb\os\win\libqb_1_2_000000000000.o"