# CFStringFindWithOptionsAndLocale(_:_:_:_:_:_:) Returns a Boolean value that indicates whether a given string was found in a given source string. ``` func CFStringFindWithOptionsAndLocale(_ theString: CFString!, _ stringToFind: CFString!, _ rangeToSearch: CFRange, _ searchOptions: CFStringCompareFlags, _ locale: CFLocale!, _ result: UnsafeMutablePointer!) -> Bool ``` ## Parameters `theString` The string in which to to search for `stringToFind`. `stringToFind` The substring to search for in `theString`. `rangeToSearch` A range of the characters to search in `theString`. The specified range must not exceed the length of the string. `searchOptions` The option flags to control the search behavior. See [String Comparison Flags](/documentation/CoreFoundation/string-comparison-flags) for possible values. The flags [`compareNumerically`](/documentation/CoreFoundation/CFStringCompareFlags/compareNumerically) and [`compareForcedOrdering`](/documentation/CoreFoundation/CFStringCompareFlags/compareForcedOrdering) are ignored. `locale` The locale to use for the search comparison. `NULL` specifies the canonical locale (the return value from [`CFLocaleGetSystem()`](/documentation/CoreFoundation/CFLocaleGetSystem())). The locale argument affects the equality checking algorithm. For example, for the Turkish locale, case-insensitive compare matches “I” to “ı” (Unicode code point U+0131, Latin Small Dotless I), not the normal “i” character. `result` On return, if the function result is `true` contains the starting location and length of the found substring. You may pass `NULL` if you only want to know if the `theString` contains `stringToFind`. ## Return Value `true` if the substring was found, `false` otherwise. ## Discussion If `stringToFind` is the empty string (zero length), nothing is found. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)