+/**
+ * Returns a locale ID for the specified BCP47 language tag string.
+ * If the specified language tag contains any ill-formed subtags,
+ * the first such subtag and all following subtags are ignored.
+ * <p>
+ * This implements the 'Language-Tag' production of BCP47, and so
+ * supports grandfathered (regular and irregular) as well as private
+ * use language tags. Private use tags are represented as 'x-whatever',
+ * and grandfathered tags are converted to their canonical replacements
+ * where they exist. Note that a few grandfathered tags have no modern
+ * replacement, these will be converted using the fallback described in
+ * the first paragraph, so some information might be lost.
+ * @param langtag the input BCP47 language tag.
+ * @param localeID the output buffer receiving a locale ID for the
+ * specified BCP47 language tag.
+ * @param localeIDCapacity the size of the locale ID output buffer.
+ * @param parsedLength if not NULL, succsessfully parsed length
+ * for the input language tag is set.
+ * @param err error information if receiving the locald ID
+ * failed.
+ * @return the length of the locale ID.
+ * @draft ICU 4.2
+ */
+U_DRAFT int32_t U_EXPORT2
+uloc_forLanguageTag(const char* langtag,
+ char* localeID,
+ int32_t localeIDCapacity,
+ int32_t* parsedLength,
+ UErrorCode* err);
+
+/**
+ * Returns a well-formed language tag for this locale ID.
+ * <p>
+ * <b>Note</b>: When <code>strict</code> is FALSE, any locale
+ * fields which do not satisfy the BCP47 syntax requirement will
+ * be omitted from the result. When <code>strict</code> is
+ * TRUE, this function sets U_ILLEGAL_ARGUMENT_ERROR to the
+ * <code>err</code> if any locale fields do not satisfy the
+ * BCP47 syntax requirement.
+ * @param localeID the input lcoale ID
+ * @param langtag the output buffer receiving BCP47 language
+ * tag for the locale ID.
+ * @param langtagCapacity the size of the BCP47 language tag
+ * output buffer.
+ * @param strict boolean value indicating if the function returns
+ * an error for an ill-formed input locale ID.
+ * @param err error information if receiving the language
+ * tag failed.
+ * @return The length of the BCP47 language tag.
+ * @draft ICU 4.2
+ */
+U_DRAFT int32_t U_EXPORT2
+uloc_toLanguageTag(const char* localeID,
+ char* langtag,
+ int32_t langtagCapacity,
+ UBool strict,
+ UErrorCode* err);
+