diff --git a/tools/unicode/c/genprops/CMakeLists.txt b/tools/unicode/c/genprops/CMakeLists.txt
index eb5f724ddc0..bbf48545a40 100644
--- a/tools/unicode/c/genprops/CMakeLists.txt
+++ b/tools/unicode/c/genprops/CMakeLists.txt
@@ -5,5 +5,5 @@
 # created by: Markus W. Scherer
 # edited on: 2010jul20
 # edited by: Stuart G. Gill
-add_executable(genprops genprops.c props2.c store.c)
+add_executable(genprops genprops.cpp props2.cpp store.c)
 target_link_libraries(genprops icuuc icutu)
diff --git a/tools/unicode/c/genprops/genprops.c b/tools/unicode/c/genprops/genprops.cpp
similarity index 99%
rename from tools/unicode/c/genprops/genprops.c
rename to tools/unicode/c/genprops/genprops.cpp
index 119ed006d06..b72dd6a5b20 100644
--- a/tools/unicode/c/genprops/genprops.c
+++ b/tools/unicode/c/genprops/genprops.cpp
@@ -1,11 +1,11 @@
 /*
 *******************************************************************************
 *
-*   Copyright (C) 1999-2008, International Business Machines
+*   Copyright (C) 1999-2010, International Business Machines
 *   Corporation and others.  All Rights Reserved.
 *
 *******************************************************************************
-*   file name:  genprops.c
+*   file name:  genprops.cpp
 *   encoding:   US-ASCII
 *   tab size:   8 (not used)
 *   indentation:4
@@ -40,6 +40,8 @@ U_CDECL_END
 
 #define LENGTHOF(array) (sizeof(array)/sizeof((array)[0]))
 
+U_NAMESPACE_USE
+
 UBool beVerbose=FALSE, haveCopyright=TRUE;
 
 /* prototypes --------------------------------------------------------------- */
diff --git a/tools/unicode/c/genprops/genprops.h b/tools/unicode/c/genprops/genprops.h
index b50a1037625..79ab229e594 100644
--- a/tools/unicode/c/genprops/genprops.h
+++ b/tools/unicode/c/genprops/genprops.h
@@ -1,7 +1,7 @@
 /*
 *******************************************************************************
 *
-*   Copyright (C) 1999-2008, International Business Machines
+*   Copyright (C) 1999-2010, International Business Machines
 *   Corporation and others.  All Rights Reserved.
 *
 *******************************************************************************
@@ -34,13 +34,13 @@ typedef struct {
 } Props;
 
 /* global flags */
-extern UBool beVerbose, haveCopyright;
+U_CFUNC UBool beVerbose, haveCopyright;
 
-extern const char *const
+U_CFUNC const char *const
 genCategoryNames[];
 
-/* properties vectors in props2.c */
-extern UPropsVectors *pv;
+/* properties vectors in props2.cpp */
+U_CFUNC UPropsVectors *pv;
 
 /* prototypes */
 U_CFUNC void
@@ -52,28 +52,28 @@ isToken(const char *token, const char *s);
 U_CFUNC int32_t
 getTokenIndex(const char *const tokens[], int32_t countTokens, const char *s);
 
-extern void
+U_CFUNC void
 setUnicodeVersion(const char *v);
 
-extern void
+U_CFUNC void
 initStore(void);
 
-extern void
+U_CFUNC void
 exitStore(void);
 
-extern uint32_t
+U_CFUNC uint32_t
 makeProps(Props *p);
 
-extern void
+U_CFUNC void
 addProps(uint32_t c, uint32_t props);
 
-extern uint32_t
+U_CFUNC uint32_t
 getProps(uint32_t c);
 
-extern void
+U_CFUNC void
 repeatProps(uint32_t first, uint32_t last, uint32_t props);
 
-extern void
+U_CFUNC void
 generateData(const char *dataDir, UBool csource);
 
 /* props2.c */
diff --git a/tools/unicode/c/genprops/props2.c b/tools/unicode/c/genprops/props2.cpp
similarity index 77%
rename from tools/unicode/c/genprops/props2.c
rename to tools/unicode/c/genprops/props2.cpp
index d1201279679..61a90f939c7 100644
--- a/tools/unicode/c/genprops/props2.c
+++ b/tools/unicode/c/genprops/props2.cpp
@@ -1,11 +1,11 @@
 /*
 *******************************************************************************
 *
-*   Copyright (C) 2002-2009, International Business Machines
+*   Copyright (C) 2002-2010, International Business Machines
 *   Corporation and others.  All Rights Reserved.
 *
 *******************************************************************************
-*   file name:  props2.c
+*   file name:  props2.cpp
 *   encoding:   US-ASCII
 *   tab size:   8 (not used)
 *   indentation:4
@@ -20,6 +20,7 @@
 #include <stdio.h>
 #include "unicode/utypes.h"
 #include "unicode/uchar.h"
+#include "unicode/unistr.h"
 #include "unicode/uscript.h"
 #include "cstring.h"
 #include "cmemory.h"
@@ -32,11 +33,15 @@
 
 #define LENGTHOF(array) (int32_t)(sizeof(array)/sizeof((array)[0]))
 
+U_NAMESPACE_USE
+
 /* data --------------------------------------------------------------------- */
 
 static UNewTrie *newTrie;
 UPropsVectors *pv;
 
+static UnicodeString *scriptExtensions;
+
 /* miscellaneous ------------------------------------------------------------ */
 
 static char *
@@ -45,7 +50,7 @@ trimTerminateField(char *s, char *limit) {
     s=(char *)u_skipWhitespace(s);
 
     /* trim trailing whitespace */
-    while(s<limit && (*(limit-1)==' ' || *(limit-1)=='\t')) {
+    while(s<limit && U_IS_INV_WHITESPACE(*(limit-1))) {
         --limit;
     }
     *limit=0;
@@ -77,6 +82,11 @@ ageLineFn(void *context,
           char *fields[][2], int32_t fieldCount,
           UErrorCode *pErrorCode);
 
+static void U_CALLCONV
+scriptExtensionsLineFn(void *context,
+                       char *fields[][2], int32_t fieldCount,
+                       UErrorCode *pErrorCode);
+
 static void
 parseMultiFieldFile(char *filename, char *basename,
                     const char *ucdFile, const char *suffix,
@@ -415,12 +425,14 @@ initAdditionalProperties() {
         fprintf(stderr, "error: upvec_open() failed - %s\n", u_errorName(errorCode));
         exit(errorCode);
     }
+    scriptExtensions=new UnicodeString;
 }
 
 U_CFUNC void
 exitAdditionalProperties() {
     utrie_close(newTrie);
     upvec_close(pv);
+    delete scriptExtensions;
 }
 
 U_CFUNC void
@@ -436,22 +448,10 @@ generateAdditionalProperties(char *filename, const char *suffix, UErrorCode *pEr
 
     parseTwoFieldFile(filename, basename, "DerivedAge", suffix, ageLineFn, pErrorCode);
 
-    /*
-     * UTR 24 says:
-     * Section 2:
-     *   "Common - For characters that may be used
-     *             within multiple scripts,
-     *             or any unassigned code points."
-     *
-     * Section 4:
-     *   "The value COMMON is the default value,
-     *    given to all code points that are not
-     *    explicitly mentioned in the data file."
-     *
-     * COMMON==USCRIPT_COMMON==0 - nothing to do
-     */
     parseSingleEnumFile(filename, basename, suffix, &scriptSingleEnum, pErrorCode);
 
+    parseTwoFieldFile(filename, basename, "ScriptExtensions", suffix, scriptExtensionsLineFn, pErrorCode);
+
     parseSingleEnumFile(filename, basename, suffix, &blockSingleEnum, pErrorCode);
 
     parseBinariesFile(filename, basename, suffix, &propListBinaries, pErrorCode);
@@ -567,6 +567,135 @@ ageLineFn(void *context,
     }
 }
 
+/* ScriptExtensions.txt ----------------------------------------------------- */
+
+static void U_CALLCONV
+scriptExtensionsLineFn(void *context,
+                       char *fields[][2], int32_t fieldCount,
+                       UErrorCode *pErrorCode) {
+    uint32_t start, end;
+    u_parseCodePointRange(fields[0][0], &start, &end, pErrorCode);
+    if(U_FAILURE(*pErrorCode)) {
+        fprintf(stderr, "genprops: syntax error in ScriptExtensions.txt field 0 at %s\n", fields[0][0]);
+        exit(*pErrorCode);
+    }
+
+    /* parse list of script codes */
+    UnicodeString codes;  // vector of 16-bit UScriptCode values
+    char *s=fields[1][0];
+    for(;;) {
+        // skip whitespace before each token
+        s=(char *)u_skipWhitespace(s);
+        if(*s==0 || *s==';') {
+            break;
+        }
+        // skip non-whitespace, non-terminator characters to find the token limit
+        char *limit=s;
+        char c;
+        do {
+            c=*++limit;
+        } while(!U_IS_INV_WHITESPACE(c) && c!=0 && c!=';');
+        // NUL-terminated this token
+        *limit=0;
+        // convert the token (script property value alias) into a UScriptCode value
+        int32_t value=u_getPropertyValueEnum(UCHAR_SCRIPT, s);
+        if(value<0) {
+            fprintf(stderr, "genprops: syntax error in ScriptExtensions.txt field 1 at %s\n", s);
+            exit(U_INVALID_FORMAT_ERROR);
+        }
+        // Insertion sort into the list of script codes.
+        for(int32_t i=0;; ++i) {
+            if(i<codes.length()) {
+                if(value<codes[i]) {
+                    codes.insert(i, (UChar)value);
+                    break;
+                } else if(value==codes[i]) {
+                    fprintf(stderr,
+                            "genprops: duplicate script code in ScriptExtensions.txt field 1 at %s "
+                            "for U+%04lx..U+%04lx\n",
+                            s, (long)start, (long)end);
+                    exit(U_INVALID_FORMAT_ERROR);
+                }
+                // continue while value>codes[i]
+            } else {
+                codes.append((UChar)value);
+                break;
+            }
+        }
+        if(c==0 || c==';') {
+            // the token ended at a terminator
+            break;
+        } else {
+            // the token ended at U_IS_INV_WHITESPACE(c), continue after c
+            s=limit+1;
+        }
+    }
+    int32_t length=codes.length();
+    if(length==0) {
+        fprintf(stderr,
+                "genprops: missing values in ScriptExtensions.txt field 1 "
+                "for U+%04lx..U+%04lx\n",
+                (long)start, (long)end);
+        exit(U_INVALID_FORMAT_ERROR);
+    }
+    // Set bit 15 on the last script code, for termination.
+    codes.setCharAt(length-1, (UChar)(codes[length-1]|0x8000));
+    // Find this list of codes in the Script_Extensions data so far, or add this list.
+    int32_t index=scriptExtensions->indexOf(codes);
+    if(index<0) {
+        index=scriptExtensions->length();
+        scriptExtensions->append(codes);
+    }
+    // Modify the Script data for each of the start..end code points
+    // to include the Script_Extensions index.
+    do {
+        uint32_t scriptX=upvec_getValue(pv, (UChar32)start, 0)&UPROPS_SCRIPT_X_MASK;
+        // Find the next code point that has a different script value.
+        // We want to add the Script_Extensions index to the code point range start..next-1.
+        UChar32 next;
+        for(next=(UChar32)start+1;
+            next<=(UChar32)end && scriptX==(upvec_getValue(pv, next, 0)&UPROPS_SCRIPT_X_MASK);
+            ++next) {}
+        if(scriptX>=UPROPS_SCRIPT_X_WITH_COMMON) {
+            fprintf(stderr,
+                    "genprops: ScriptExtensions.txt has values for U+%04lx..U+%04lx "
+                    "which overlaps with a range including U+%04lx..U+%04lx\n",
+                    (long)start, (long)end, (long)start, (long)(next-1));
+            exit(U_INVALID_FORMAT_ERROR);
+        }
+        // Encode the (Script, Script_Extensions index) pair.
+        if(scriptX==USCRIPT_COMMON) {
+            scriptX=UPROPS_SCRIPT_X_WITH_COMMON|(uint32_t)index;
+        } else if(scriptX==USCRIPT_INHERITED) {
+            scriptX=UPROPS_SCRIPT_X_WITH_INHERITED|(uint32_t)index;
+        } else {
+            // Store an additional pair of 16-bit units for an unusual main Script code
+            // together with the Script_Extensions index.
+            UnicodeString codeIndexPair;
+            codeIndexPair.append((UChar)scriptX).append((UChar)index);
+            index=scriptExtensions->indexOf(codeIndexPair);
+            if(index<0) {
+                index=scriptExtensions->length();
+                scriptExtensions->append(codeIndexPair);
+            }
+            scriptX=UPROPS_SCRIPT_X_WITH_OTHER|(uint32_t)index;
+        }
+        if(index>UPROPS_SCRIPT_MASK) {
+            fprintf(stderr, "genprops: Script_Extensions indexes overflow bit field\n");
+            exit(U_BUFFER_OVERFLOW_ERROR);
+        }
+        // Write the (Script, Script_Extensions index) pair into
+        // the properties vector for start..next-1.
+        upvec_setValue(pv, (UChar32)start, (UChar32)(next-1),
+                        0, scriptX, UPROPS_SCRIPT_X_MASK, pErrorCode);
+        if(U_FAILURE(*pErrorCode)) {
+            fprintf(stderr, "genprops error: unable to set Script_Extensions: %s\n", u_errorName(*pErrorCode));
+            exit(*pErrorCode);
+        }
+        start=next;
+    } while(start<=end);
+}
+
 /* DerivedNumericValues.txt ------------------------------------------------- */
 
 static void U_CALLCONV
@@ -719,7 +848,36 @@ writeAdditionalData(FILE *f, uint8_t *p, int32_t capacity, int32_t indexes[UPROP
         fprintf(stderr, "genprops error: unable to serialize trie for additional properties: %s\n", u_errorName(errorCode));
         exit(errorCode);
     }
-    if(p!=NULL) {
+
+    /* round up scriptExtensions to multiple of 4 bytes */
+    if(scriptExtensions->length()&1) {
+        scriptExtensions->append((UChar)0);
+    }
+
+    /* set indexes */
+    indexes[UPROPS_ADDITIONAL_VECTORS_INDEX]=
+        indexes[UPROPS_ADDITIONAL_TRIE_INDEX]+length/4;
+    indexes[UPROPS_ADDITIONAL_VECTORS_COLUMNS_INDEX]=UPROPS_VECTOR_WORDS;
+    indexes[UPROPS_SCRIPT_EXTENSIONS_INDEX]=
+        indexes[UPROPS_ADDITIONAL_VECTORS_INDEX]+pvCount;
+    indexes[UPROPS_RESERVED_INDEX_7]=
+        indexes[UPROPS_SCRIPT_EXTENSIONS_INDEX]+scriptExtensions->length()/2;
+    indexes[UPROPS_RESERVED_INDEX_8]=indexes[UPROPS_RESERVED_INDEX_7];
+    indexes[UPROPS_DATA_TOP_INDEX]=indexes[UPROPS_RESERVED_INDEX_8];
+
+    indexes[UPROPS_MAX_VALUES_INDEX]=
+        (((int32_t)U_EA_COUNT-1)<<UPROPS_EA_SHIFT)|
+        (((int32_t)UBLOCK_COUNT-1)<<UPROPS_BLOCK_SHIFT)|
+        (((int32_t)USCRIPT_CODE_LIMIT-1)&UPROPS_SCRIPT_MASK);
+    indexes[UPROPS_MAX_VALUES_2_INDEX]=
+        (((int32_t)U_LB_COUNT-1)<<UPROPS_LB_SHIFT)|
+        (((int32_t)U_SB_COUNT-1)<<UPROPS_SB_SHIFT)|
+        (((int32_t)U_WB_COUNT-1)<<UPROPS_WB_SHIFT)|
+        (((int32_t)U_GCB_COUNT-1)<<UPROPS_GCB_SHIFT)|
+        ((int32_t)U_DT_COUNT-1);
+
+    int32_t additionalPropsSize=4*(indexes[UPROPS_DATA_TOP_INDEX]-indexes[UPROPS_ADDITIONAL_TRIE_INDEX]);
+    if(p!=NULL && additionalPropsSize<=capacity) {
         if(beVerbose) {
             printf("size in bytes of additional props trie:%5u\n", (int)length);
         }
@@ -756,7 +914,7 @@ writeAdditionalData(FILE *f, uint8_t *p, int32_t capacity, int32_t indexes[UPROP
                 if(U_FAILURE(errorCode)) {
                     fprintf(
                         stderr,
-                        "genbidi error: deleting lead surrogate code unit values failed - %s\n",
+                        "genprops error: deleting lead surrogate code unit values failed - %s\n",
                         u_errorName(errorCode));
                     exit(errorCode);
                 }
@@ -772,47 +930,33 @@ writeAdditionalData(FILE *f, uint8_t *p, int32_t capacity, int32_t indexes[UPROP
                 "};\n\n");
 
             utrie2_close(trie2);
-        }
 
-        p+=length;
-        capacity-=length;
-
-        /* set indexes */
-        indexes[UPROPS_ADDITIONAL_VECTORS_INDEX]=
-            indexes[UPROPS_ADDITIONAL_TRIE_INDEX]+length/4;
-        indexes[UPROPS_ADDITIONAL_VECTORS_COLUMNS_INDEX]=UPROPS_VECTOR_WORDS;
-        indexes[UPROPS_RESERVED_INDEX]=
-            indexes[UPROPS_ADDITIONAL_VECTORS_INDEX]+pvCount;
-
-        indexes[UPROPS_MAX_VALUES_INDEX]=
-            (((int32_t)U_EA_COUNT-1)<<UPROPS_EA_SHIFT)|
-            (((int32_t)UBLOCK_COUNT-1)<<UPROPS_BLOCK_SHIFT)|
-            (((int32_t)USCRIPT_CODE_LIMIT-1)&UPROPS_SCRIPT_MASK);
-        indexes[UPROPS_MAX_VALUES_2_INDEX]=
-            (((int32_t)U_LB_COUNT-1)<<UPROPS_LB_SHIFT)|
-            (((int32_t)U_SB_COUNT-1)<<UPROPS_SB_SHIFT)|
-            (((int32_t)U_WB_COUNT-1)<<UPROPS_WB_SHIFT)|
-            (((int32_t)U_GCB_COUNT-1)<<UPROPS_GCB_SHIFT)|
-            ((int32_t)U_DT_COUNT-1);
-    }
-
-    if(p!=NULL && (pvCount*4)<=capacity) {
-        if(f!=NULL) {
             usrc_writeArray(f,
                 "static const uint32_t propsVectors[%ld]={\n",
                 pvArray, 32, pvCount,
                 "};\n\n");
             fprintf(f, "static const int32_t countPropsVectors=%ld;\n", (long)pvCount);
             fprintf(f, "static const int32_t propsVectorsColumns=%ld;\n", (long)indexes[UPROPS_ADDITIONAL_VECTORS_COLUMNS_INDEX]);
+
+            usrc_writeArray(f,
+                "static const uint16_t scriptExtensions[%ld]={\n",
+                scriptExtensions->getBuffer(), 16, scriptExtensions->length(),
+                "};\n\n");
         } else {
-            uprv_memcpy(p, pvArray, pvCount*4);
+            p+=length;
+            length=pvCount*4;
+            uprv_memcpy(p, pvArray, length);
+
+            p+=length;
+            length=scriptExtensions->length()*2;
+            uprv_memcpy(p, scriptExtensions->getBuffer(), length);
         }
         if(beVerbose) {
             printf("number of additional props vectors:    %5u\n", (int)pvRows);
             printf("number of 32-bit words per vector:     %5u\n", UPROPS_VECTOR_WORDS);
+            printf("number of 16-bit scriptExtensions:     %5u\n", (int)scriptExtensions->length());
         }
     }
-    length+=pvCount*4;
 
-    return length;
+    return additionalPropsSize;
 }
diff --git a/tools/unicode/c/genprops/store.c b/tools/unicode/c/genprops/store.c
index 4499073a956..1874441ac16 100644
--- a/tools/unicode/c/genprops/store.c
+++ b/tools/unicode/c/genprops/store.c
@@ -41,7 +41,7 @@ the udata API for loading ICU data. Especially, a UDataInfo structure
 precedes the actual data. It contains platform properties values and the
 file format version.
 
-The following is a description of format version 6 .
+The following is a description of format version 7 .
 
 Data contents:
 
@@ -74,8 +74,10 @@ Formally, the file contains the following structures:
     i4 additionalVectorsIndex; -- 32-bit unit index to the table of properties vectors
     i5 additionalVectorsColumns; -- number of 32-bit words per properties vector
 
-    i6 reservedItemIndex; -- 32-bit unit index to the top of the properties vectors table
-    i7..i9 reservedIndexes; -- reserved values; 0 for now
+    i6 scriptExtensionsIndex; -- 32-bit unit index to the Script_Extensions data
+    i7 reservedIndex7; -- 32-bit unit index to the top of the Script_Extensions data
+    i8 reservedIndex8; -- for now: i7, i8 and i9 have the same values
+    i9 dataTopIndex; -- size of the data file (number of 32-bit units after the header)
 
     i10 maxValues; -- maximum code values for vector word 0, see uprops.h (new in format version 3.1+)
     i11 maxValues2; -- maximum code values for vector word 2, see uprops.h (new in format version 3.2)
@@ -92,6 +94,20 @@ Formally, the file contains the following structures:
     AT serialized trie for additional properties (byte size: 4*(i4-i3))
     PV const uint32_t propsVectors[(i6-i4)/i5][i5]==uint32_t propsVectors[i6-i4];
 
+    SCX const uint16_t scriptExtensions[2*(i7-i6)];
+
+      SCX contains Script_Extensions lists and (Script code, Script_Extensions index) pairs.
+      A Script_Extensions list is a sequence of UScriptCode values in ascending order,
+      with the last code having bit 15 set for termination.
+      A (Script code, Script_Extensions index) pair is the main UScriptCode (Script value)
+      followed by the index of the Script_Extensions list.
+      If the propsVectors[] column 0 value indicates that there are Script_Extensions,
+      then the UPROPS_SCRIPT_MASK bit field is an index to either a list or a pair in SCX,
+      rather than the Script itself. The high bits in the UPROPS_SCRIPT_X_MASK fields
+      indicate whether the main Script value is Common or Inherited (and the index is to a list)
+      vs. another value (and the index is to a pair).
+      (See UPROPS_SCRIPT_X_WITH_COMMON etc. in uprops.h.)
+
 Trie lookup and properties:
 
 In order to condense the data for the 21-bit code space, several properties of
@@ -206,6 +222,12 @@ Format version 6 became necessary because Unicode 5.2 adds fractions with
 denominators 9, 10 and 16, and it was easier to redesign the encoding of numeric
 types and values rather than add another variant to the previous format.
 
+--- Changes in format version 7 ---
+
+Unicode 6.0 adds Script_Extensions. For characters with script extensions data,
+the script code bits are an index into the new Script_Extensions array rather
+than a script code.
+
 ----------------------------------------------------------------------------- */
 
 /* UDataInfo cf. udata.h */
@@ -227,14 +249,14 @@ static UNewTrie *pTrie=NULL;
 
 /* -------------------------------------------------------------------------- */
 
-extern void
+U_CFUNC void
 setUnicodeVersion(const char *v) {
     UVersionInfo version;
     u_versionFromString(version, v);
     uprv_memcpy(dataInfo.dataVersion, version, 4);
 }
 
-extern void
+U_CFUNC void
 initStore() {
     pTrie=utrie_open(NULL, NULL, 40000, 0, 0, TRUE);
     if(pTrie==NULL) {
@@ -245,7 +267,7 @@ initStore() {
     initAdditionalProperties();
 }
 
-extern void
+U_CFUNC void
 exitStore() {
     utrie_close(pTrie);
     exitAdditionalProperties();
@@ -253,7 +275,7 @@ exitStore() {
 
 /* store a character's properties ------------------------------------------- */
 
-extern uint32_t
+U_CFUNC uint32_t
 makeProps(Props *p) {
     uint32_t den;
     int32_t type, value, exp, ntv;
@@ -327,7 +349,7 @@ makeProps(Props *p) {
         (ntv<<UPROPS_NUMERIC_TYPE_VALUE_SHIFT);
 }
 
-extern void
+U_CFUNC void
 addProps(uint32_t c, uint32_t x) {
     if(!utrie_set32(pTrie, (UChar32)c, x)) {
         fprintf(stderr, "error: too many entries for the properties trie\n");
@@ -335,14 +357,14 @@ addProps(uint32_t c, uint32_t x) {
     }
 }
 
-extern uint32_t
+U_CFUNC uint32_t
 getProps(uint32_t c) {
     return utrie_get32(pTrie, (UChar32)c, NULL);
 }
 
 /* areas of same properties ------------------------------------------------- */
 
-extern void
+U_CFUNC void
 repeatProps(uint32_t first, uint32_t last, uint32_t x) {
     if(!utrie_setRange32(pTrie, (UChar32)first, (UChar32)(last+1), x, FALSE)) {
         fprintf(stderr, "error: too many entries for the properties trie\n");
@@ -352,7 +374,7 @@ repeatProps(uint32_t first, uint32_t last, uint32_t x) {
 
 /* generate output data ----------------------------------------------------- */
 
-extern void
+U_CFUNC void
 generateData(const char *dataDir, UBool csource) {
     static int32_t indexes[UPROPS_INDEX_COUNT]={
         0, 0, 0, 0,