diff --git a/ext/intl/common/common_date.h b/ext/intl/common/common_date.h
index ef007c8eee687..988f279294c3c 100644
--- a/ext/intl/common/common_date.h
+++ b/ext/intl/common/common_date.h
@@ -24,6 +24,9 @@ U_CDECL_END
 
 #ifdef __cplusplus
 
+// TODO once C++ migration done we can drop this workaround
+#undef U_SHOW_CPLUSPLUS_API
+#define U_SHOW_CPLUSPLUS_API 1
 #include <unicode/timezone.h>
 
 using icu::TimeZone;
diff --git a/ext/intl/config.m4 b/ext/intl/config.m4
index c4c3c9b1d4cea..17b9dbf68d6f3 100644
--- a/ext/intl/config.m4
+++ b/ext/intl/config.m4
@@ -18,19 +18,8 @@ if test "$PHP_INTL" != "no"; then
       collator/collator_locale.c
       collator/collator_sort.c
       common/common_error.c
-      converter/converter.c
-      dateformat/dateformat_attr.c
       dateformat/dateformat_class.c
-      dateformat/dateformat_data.c
-      dateformat/dateformat_format.c
-      dateformat/dateformat_parse.c
-      dateformat/dateformat.c
-      formatter/formatter_attr.c
       formatter/formatter_class.c
-      formatter/formatter_data.c
-      formatter/formatter_format.c
-      formatter/formatter_main.c
-      formatter/formatter_parse.c
       grapheme/grapheme_string.c
       grapheme/grapheme_util.c
       intl_convert.c
@@ -53,10 +42,16 @@ if test "$PHP_INTL" != "no"; then
   PHP_INTL_CXX_SOURCES="intl_convertcpp.cpp \
     common/common_enum.cpp \
     common/common_date.cpp \
-    dateformat/dateformat_format_object.cpp \
-    dateformat/dateformat_create.cpp \
+    converter/converter.cpp \
+    dateformat/dateformat.cpp \
+    dateformat/dateformat_attr.cpp \
     dateformat/dateformat_attrcpp.cpp \
+    dateformat/dateformat_create.cpp \
+    dateformat/dateformat_data.cpp \
+    dateformat/dateformat_format.cpp \
+    dateformat/dateformat_format_object.cpp \
     dateformat/dateformat_helpers.cpp \
+    dateformat/dateformat_parse.cpp \
     dateformat/datepatterngenerator_class.cpp \
     dateformat/datepatterngenerator_methods.cpp \
     msgformat/msgformat_helpers.cpp \
@@ -65,6 +60,11 @@ if test "$PHP_INTL" != "no"; then
     calendar/calendar_class.cpp \
     calendar/calendar_methods.cpp \
     calendar/gregoriancalendar_methods.cpp \
+    formatter/formatter_attr.cpp \
+    formatter/formatter_data.cpp \
+    formatter/formatter_format.cpp \
+    formatter/formatter_main.cpp \
+    formatter/formatter_parse.cpp \
     msgformat/msgformat_attr.cpp \
     msgformat/msgformat_class.cpp \
     msgformat/msgformat_data.cpp \
diff --git a/ext/intl/config.w32 b/ext/intl/config.w32
index fb3f0212729dd..f0183d84949fc 100644
--- a/ext/intl/config.w32
+++ b/ext/intl/config.w32
@@ -29,15 +29,15 @@ if (PHP_INTL != "no") {
 				common_date.cpp \
 				", "intl");
 		ADD_SOURCES(configure_module_dirname + "/converter", "\
-				converter.c \
+				converter.cpp \
 				", "intl");
 		ADD_SOURCES(configure_module_dirname + "/formatter", "\
-				formatter_attr.c \
+				formatter_attr.cpp \
 				formatter_class.c \
-				formatter_data.c \
-				formatter_format.c \
-				formatter_main.c \
-				formatter_parse.c \
+				formatter_data.cpp \
+				formatter_format.cpp \
+				formatter_main.cpp \
+				formatter_parse.cpp \
 				", "intl");
 		ADD_SOURCES(configure_module_dirname + "/listformatter", "\
 				listformatter_class.c \
@@ -64,13 +64,13 @@ if (PHP_INTL != "no") {
 				normalizer_normalize.cpp \
 				", "intl");
 		ADD_SOURCES(configure_module_dirname + "/dateformat", "\
-				dateformat.c \
+				dateformat.cpp \
 				dateformat_class.c \
-				dateformat_attr.c \
-				dateformat_format.c \
+				dateformat_attr.cpp \
+				dateformat_format.cpp \
 				dateformat_format_object.cpp \
-				dateformat_parse.c \
-				dateformat_data.c \
+				dateformat_parse.cpp \
+				dateformat_data.cpp \
 				dateformat_attrcpp.cpp \
 				dateformat_helpers.cpp \
 				dateformat_create.cpp \
diff --git a/ext/intl/converter/converter.c b/ext/intl/converter/converter.cpp
similarity index 95%
rename from ext/intl/converter/converter.c
rename to ext/intl/converter/converter.cpp
index 759db5e18873a..6123d4b49e614 100644
--- a/ext/intl/converter/converter.c
+++ b/ext/intl/converter/converter.cpp
@@ -12,7 +12,6 @@
    +----------------------------------------------------------------------+
  */
 
-#include "converter.h"
 #include "zend_exceptions.h"
 
 #include <unicode/utypes.h>
@@ -21,10 +20,13 @@
 #include <unicode/ucnv.h>
 #include <unicode/ustring.h>
 
+extern "C" {
+#include "converter.h"
+#include "php_intl.h"
 #include "../intl_error.h"
 #include "../intl_common.h"
+}
 #include "converter_arginfo.h"
-#include "php_intl.h"
 
 typedef struct _php_converter_object {
 	UConverter *src, *dest;
@@ -238,9 +240,9 @@ static void php_converter_to_u_callback(const void *context,
 	}
 
 	if (Z_TYPE(zargs[3]) == IS_LONG) {
-		*pErrorCode = Z_LVAL(zargs[3]);
+		*pErrorCode = static_cast<UErrorCode>(Z_LVAL(zargs[3]));
 	} else if (Z_ISREF(zargs[3]) && Z_TYPE_P(Z_REFVAL(zargs[3])) == IS_LONG) {
-		*pErrorCode = Z_LVAL_P(Z_REFVAL(zargs[3]));
+		*pErrorCode = static_cast<UErrorCode>(Z_LVAL_P(Z_REFVAL(zargs[3])));
 	}
 
 	zval_ptr_dtor(&zargs[0]);
@@ -265,7 +267,7 @@ static void php_converter_append_fromUnicode_target(zval *val, UConverterFromUni
 		{
 			size_t vallen = Z_STRLEN_P(val);
 			if (TARGET_CHECK(args, vallen)) {
-				args->target = zend_mempcpy(args->target, Z_STRVAL_P(val), vallen);
+				args->target = reinterpret_cast<char *>(zend_mempcpy(args->target, Z_STRVAL_P(val), vallen));
 			}
 			return;
 		}
@@ -315,9 +317,9 @@ static void php_converter_from_u_callback(const void *context,
 	}
 
 	if (Z_TYPE(zargs[3]) == IS_LONG) {
-		*pErrorCode = Z_LVAL(zargs[3]);
+		*pErrorCode = static_cast<UErrorCode>(Z_LVAL(zargs[3]));
 	} else if (Z_ISREF(zargs[3]) && Z_TYPE_P(Z_REFVAL(zargs[3])) == IS_LONG) {
-		*pErrorCode = Z_LVAL_P(Z_REFVAL(zargs[3]));
+		*pErrorCode = static_cast<UErrorCode>(Z_LVAL_P(Z_REFVAL(zargs[3])));
 	}
 
 	zval_ptr_dtor(&zargs[0]);
@@ -340,7 +342,7 @@ static inline bool php_converter_set_callbacks(php_converter_object *objval, UCo
 	}
 
 	ucnv_setToUCallBack(cnv, (UConverterToUCallback)php_converter_to_u_callback, (const void*)objval,
-	                    NULL, NULL, &error);
+	                    nullptr, nullptr, &error);
 	if (U_FAILURE(error)) {
 		THROW_UFAILURE(objval, error);
 		ret = 0;
@@ -348,7 +350,7 @@ static inline bool php_converter_set_callbacks(php_converter_object *objval, UCo
 
 	error = U_ZERO_ERROR;
 	ucnv_setFromUCallBack(cnv, (UConverterFromUCallback)php_converter_from_u_callback, (const void*)objval,
-	                      NULL, NULL, &error);
+	                      nullptr, nullptr, &error);
 	if (U_FAILURE(error)) {
 		THROW_UFAILURE(objval, error);
 		ret = 0;
@@ -507,14 +509,14 @@ static void php_converter_resolve_callback(
 	const char *callback_name,
 	size_t callback_name_len
 ) {
-	zend_function *fn = zend_hash_str_find_ptr_lc(&obj->ce->function_table, callback_name, callback_name_len);
-	ZEND_ASSERT(fn != NULL);
+	zend_function *fn = reinterpret_cast<zend_function *>(zend_hash_str_find_ptr_lc(&obj->ce->function_table, callback_name, callback_name_len));
+	ZEND_ASSERT(fn != nullptr);
 
 	fcc->function_handler = fn;
 	fcc->object = obj;
 	fcc->called_scope = obj->ce;
-	fcc->calling_scope = NULL;
-	fcc->closure = NULL;
+	fcc->calling_scope = nullptr;
+	fcc->closure = nullptr;
 }
 /* }}} */
 
@@ -635,16 +637,16 @@ static zend_string* php_converter_do_convert(UConverter *dest_cnv,
 	if (!src_cnv || !dest_cnv) {
 		php_converter_throw_failure(objval, U_INVALID_STATE_ERROR,
 		                            "Internal converters not initialized");
-		return NULL;
+		return nullptr;
 	}
 
 	/* Get necessary buffer size first */
 	temp_len = 1 + ucnv_toUChars(src_cnv, NULL, 0, src, src_len, &error);
 	if (U_FAILURE(error) && error != U_BUFFER_OVERFLOW_ERROR) {
 		THROW_UFAILURE(objval, error);
-		return NULL;
+		return nullptr;
 	}
-	temp = safe_emalloc(sizeof(UChar), temp_len, sizeof(UChar));
+	temp = reinterpret_cast<UChar *>(safe_emalloc(sizeof(UChar), temp_len, sizeof(UChar)));
 
 	/* Convert to intermediate UChar* array */
 	error = U_ZERO_ERROR;
@@ -652,7 +654,7 @@ static zend_string* php_converter_do_convert(UConverter *dest_cnv,
 	if (U_FAILURE(error)) {
 		THROW_UFAILURE(objval, error);
 		efree(temp);
-		return NULL;
+		return nullptr;
 	}
 	temp[temp_len] = 0;
 
@@ -661,7 +663,7 @@ static zend_string* php_converter_do_convert(UConverter *dest_cnv,
 	if (U_FAILURE(error) && error != U_BUFFER_OVERFLOW_ERROR) {
 		THROW_UFAILURE(objval, error);
 		efree(temp);
-		return NULL;
+		return nullptr;
 	}
 
 	ret = zend_string_alloc(ret_len, 0);
@@ -673,7 +675,7 @@ static zend_string* php_converter_do_convert(UConverter *dest_cnv,
 	if (U_FAILURE(error)) {
 		THROW_UFAILURE(objval, error);
 		zend_string_efree(ret);
-		return NULL;
+		return nullptr;
 	}
 
 	return ret;
@@ -735,8 +737,8 @@ PHP_METHOD(UConverter, convert) {
 PHP_METHOD(UConverter, transcode) {
 	char *str, *src, *dest;
 	size_t str_len, src_len, dest_len;
-	zval *options = NULL;
-	UConverter *src_cnv = NULL, *dest_cnv = NULL;
+	zval *options = nullptr;
+	UConverter *src_cnv = nullptr, *dest_cnv = nullptr;
 
 	ZEND_PARSE_PARAMETERS_START(3, 4)
 		Z_PARAM_STRING(str, str_len)
@@ -911,7 +913,7 @@ static void php_converter_free_object(zend_object *obj) {
 static zend_object *php_converter_object_ctor(zend_class_entry *ce, php_converter_object **pobjval) {
 	php_converter_object *objval;
 
-	objval = zend_object_alloc(sizeof(php_converter_object), ce);
+	objval = reinterpret_cast<php_converter_object *>(zend_object_alloc(sizeof(php_converter_object), ce));
 
 	zend_object_std_init(&objval->obj, ce);
 	object_properties_init(&objval->obj, ce);
@@ -923,7 +925,7 @@ static zend_object *php_converter_object_ctor(zend_class_entry *ce, php_converte
 }
 
 static zend_object *php_converter_create_object(zend_class_entry *ce) {
-	php_converter_object *objval = NULL;
+	php_converter_object *objval = nullptr;
 	zend_object *retval = php_converter_object_ctor(ce, &objval);
 
 	object_properties_init(&(objval->obj), ce);
@@ -968,7 +970,7 @@ static zend_object *php_converter_clone_object(zend_object *object) {
 /* }}} */
 
 /* {{{ php_converter_minit */
-int php_converter_minit(INIT_FUNC_ARGS) {
+U_CFUNC int php_converter_minit(INIT_FUNC_ARGS) {
 	php_converter_ce = register_class_UConverter();
 	php_converter_ce->create_object = php_converter_create_object;
 	php_converter_ce->default_object_handlers = &php_converter_object_handlers;
diff --git a/ext/intl/converter/converter.h b/ext/intl/converter/converter.h
index f9fb27b82a7d0..5d779560811d0 100644
--- a/ext/intl/converter/converter.h
+++ b/ext/intl/converter/converter.h
@@ -21,6 +21,12 @@
 
 #include "php.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
 int php_converter_minit(INIT_FUNC_ARGS);
+#ifdef __cplusplus
+}
+#endif
 
 #endif /* PHP_INTL_CONVERTER_H */
diff --git a/ext/intl/dateformat/dateformat.c b/ext/intl/dateformat/dateformat.cpp
similarity index 94%
rename from ext/intl/dateformat/dateformat.c
rename to ext/intl/dateformat/dateformat.cpp
index e6ebd5b789649..cf2b445590bb9 100644
--- a/ext/intl/dateformat/dateformat.c
+++ b/ext/intl/dateformat/dateformat.cpp
@@ -17,12 +17,14 @@
 
 #include <unicode/udat.h>
 
+extern "C" {
 #include "php_intl.h"
+}
 #include "dateformat_class.h"
 #include "dateformat.h"
 
 /* {{{ Get formatter's last error code. */
-PHP_FUNCTION( datefmt_get_error_code )
+U_CFUNC PHP_FUNCTION( datefmt_get_error_code )
 {
 	DATE_FORMAT_METHOD_INIT_VARS;
 
@@ -41,7 +43,7 @@ PHP_FUNCTION( datefmt_get_error_code )
 /* }}} */
 
 /* {{{ Get text description for formatter's last error code. */
-PHP_FUNCTION( datefmt_get_error_message )
+U_CFUNC PHP_FUNCTION( datefmt_get_error_message )
 {
 	zend_string *message = NULL;
 	DATE_FORMAT_METHOD_INIT_VARS;
diff --git a/ext/intl/dateformat/dateformat_attr.c b/ext/intl/dateformat/dateformat_attr.cpp
similarity index 90%
rename from ext/intl/dateformat/dateformat_attr.c
rename to ext/intl/dateformat/dateformat_attr.cpp
index 8032d758a939b..9c0a1a700be1b 100644
--- a/ext/intl/dateformat/dateformat_attr.c
+++ b/ext/intl/dateformat/dateformat_attr.cpp
@@ -15,16 +15,18 @@
 #include <config.h>
 #endif
 
+extern "C" {
 #include "../php_intl.h"
-#include "dateformat_class.h"
 #include "../intl_convert.h"
+}
+#include "dateformat_class.h"
 #include "dateformat_class.h"
 
 #include <unicode/ustring.h>
 #include <unicode/udat.h>
 
 /* {{{ Get formatter datetype. */
-PHP_FUNCTION( datefmt_get_datetype )
+U_CFUNC PHP_FUNCTION( datefmt_get_datetype )
 {
 	DATE_FORMAT_METHOD_INIT_VARS;
 
@@ -44,7 +46,7 @@ PHP_FUNCTION( datefmt_get_datetype )
 /* }}} */
 
 /* {{{ Get formatter timetype. */
-PHP_FUNCTION( datefmt_get_timetype )
+U_CFUNC PHP_FUNCTION( datefmt_get_timetype )
 {
 	DATE_FORMAT_METHOD_INIT_VARS;
 
@@ -64,7 +66,7 @@ PHP_FUNCTION( datefmt_get_timetype )
 /* }}} */
 
 /* {{{ Get formatter pattern. */
-PHP_FUNCTION( datefmt_get_pattern )
+U_CFUNC PHP_FUNCTION( datefmt_get_pattern )
 {
 	UChar  value_buf[64];
 	uint32_t    length = USIZE( value_buf );
@@ -100,12 +102,12 @@ PHP_FUNCTION( datefmt_get_pattern )
 /* }}} */
 
 /* {{{ Set formatter pattern. */
-PHP_FUNCTION( datefmt_set_pattern )
+U_CFUNC PHP_FUNCTION( datefmt_set_pattern )
 {
-	char*       value = NULL;
+	char*       value = nullptr;
 	size_t      value_len = 0;
 	int32_t     slength = 0;
-	UChar*	    svalue  = NULL;
+	UChar*	    svalue  = nullptr;
 	bool   is_pattern_localized = false;
 
 
@@ -136,7 +138,7 @@ PHP_FUNCTION( datefmt_set_pattern )
 /* }}} */
 
 /* {{{ Get formatter locale. */
-PHP_FUNCTION( datefmt_get_locale )
+U_CFUNC PHP_FUNCTION( datefmt_get_locale )
 {
 	char *loc;
 	zend_long  loc_type =ULOC_ACTUAL_LOCALE;
@@ -154,14 +156,14 @@ PHP_FUNCTION( datefmt_get_locale )
 	/* Fetch the object. */
 	DATE_FORMAT_METHOD_FETCH_OBJECT;
 
-	loc = (char *)udat_getLocaleByType(DATE_FORMAT_OBJECT(dfo), loc_type,&INTL_DATA_ERROR_CODE(dfo));
+	loc = (char *)udat_getLocaleByType(DATE_FORMAT_OBJECT(dfo), static_cast<ULocDataLocaleType>(loc_type),&INTL_DATA_ERROR_CODE(dfo));
 	INTL_METHOD_CHECK_STATUS(dfo, "Error getting locale");
 	RETURN_STRING(loc);
 }
 /* }}} */
 
 /* {{{ Get formatter isLenient. */
-PHP_FUNCTION( datefmt_is_lenient )
+U_CFUNC PHP_FUNCTION( datefmt_is_lenient )
 {
 
 	DATE_FORMAT_METHOD_INIT_VARS;
@@ -182,7 +184,7 @@ PHP_FUNCTION( datefmt_is_lenient )
 /* }}} */
 
 /* {{{ Set formatter lenient. */
-PHP_FUNCTION( datefmt_set_lenient )
+U_CFUNC PHP_FUNCTION( datefmt_set_lenient )
 {
 	bool isLenient = false;
 
diff --git a/ext/intl/dateformat/dateformat_class.h b/ext/intl/dateformat/dateformat_class.h
index 18afb55023b42..167a777e405fa 100644
--- a/ext/intl/dateformat/dateformat_class.h
+++ b/ext/intl/dateformat/dateformat_class.h
@@ -35,8 +35,14 @@ static inline IntlDateFormatter_object *php_intl_dateformatter_fetch_object(zend
 }
 #define Z_INTL_DATEFORMATTER_P(zv) php_intl_dateformatter_fetch_object(Z_OBJ_P(zv))
 
+#ifdef __cplusplus
+extern "C" {
+#endif
 void dateformat_register_IntlDateFormatter_class( void );
 extern zend_class_entry *IntlDateFormatter_ce_ptr;
+#ifdef __cplusplus
+}
+#endif
 
 /* Auxiliary macros */
 
diff --git a/ext/intl/dateformat/dateformat_data.c b/ext/intl/dateformat/dateformat_data.cpp
similarity index 91%
rename from ext/intl/dateformat/dateformat_data.c
rename to ext/intl/dateformat/dateformat_data.cpp
index 9c12af6fb6059..42e7c9522055f 100644
--- a/ext/intl/dateformat/dateformat_data.c
+++ b/ext/intl/dateformat/dateformat_data.cpp
@@ -25,7 +25,7 @@ void dateformat_data_init( dateformat_data* datef_data )
 	if( !datef_data )
 		return;
 
-	datef_data->udatf = NULL;
+	datef_data->udatf = nullptr;
 	intl_error_reset( &datef_data->error );
 }
 /* }}} */
@@ -41,7 +41,7 @@ void dateformat_data_free( dateformat_data* datef_data )
 	if( datef_data->udatf )
 		udat_close( datef_data->udatf );
 
-	datef_data->udatf = NULL;
+	datef_data->udatf = nullptr;
 	intl_error_reset( &datef_data->error );
 }
 /* }}} */
@@ -51,7 +51,7 @@ void dateformat_data_free( dateformat_data* datef_data )
  */
 dateformat_data* dateformat_data_create( void )
 {
-	dateformat_data* datef_data = ecalloc( 1, sizeof(dateformat_data) );
+	dateformat_data* datef_data = reinterpret_cast<dateformat_data *>(ecalloc( 1, sizeof(dateformat_data) ));
 
 	dateformat_data_init( datef_data );
 
diff --git a/ext/intl/dateformat/dateformat_data.h b/ext/intl/dateformat/dateformat_data.h
index 4007d1344fbb6..962ffbade31d8 100644
--- a/ext/intl/dateformat/dateformat_data.h
+++ b/ext/intl/dateformat/dateformat_data.h
@@ -18,7 +18,13 @@
 
 #include <unicode/udat.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
 #include "intl_error.h"
+#ifdef __cplusplus
+}
+#endif
 
 typedef struct {
 	// error handling
@@ -28,8 +34,14 @@ typedef struct {
 	UDateFormat *  udatf;
 } dateformat_data;
 
+#ifdef __cplusplus
+extern "C" {
+#endif
 dateformat_data* dateformat_data_create( void );
 void dateformat_data_init( dateformat_data* datef_data );
 void dateformat_data_free( dateformat_data* datef_data );
+#ifdef __cplusplus
+}
+#endif
 
 #endif // DATE_FORMAT_DATA_H
diff --git a/ext/intl/dateformat/dateformat_format.c b/ext/intl/dateformat/dateformat_format.cpp
similarity index 99%
rename from ext/intl/dateformat/dateformat_format.c
rename to ext/intl/dateformat/dateformat_format.cpp
index ee3abd052d669..4e9531a86ce54 100644
--- a/ext/intl/dateformat/dateformat_format.c
+++ b/ext/intl/dateformat/dateformat_format.cpp
@@ -16,12 +16,14 @@
 #include <config.h>
 #endif
 
+extern "C" {
 #include "../php_intl.h"
+#include "../intl_convert.h"
+}
 
 #include <unicode/ustring.h>
 #include <unicode/ucal.h>
 
-#include "../intl_convert.h"
 #include "../common/common_date.h"
 #include "dateformat.h"
 #include "dateformat_class.h"
@@ -137,7 +139,7 @@ static UDate internal_get_timestamp(IntlDateFormatter_object *dfo,
 
 
 /* {{{ Format the time value as a string. */
-PHP_FUNCTION(datefmt_format)
+U_CFUNC PHP_FUNCTION(datefmt_format)
 {
 	UDate 		timestamp	= 0;
 	HashTable	*hash_arr	= NULL;
diff --git a/ext/intl/dateformat/dateformat_parse.c b/ext/intl/dateformat/dateformat_parse.cpp
similarity index 96%
rename from ext/intl/dateformat/dateformat_parse.c
rename to ext/intl/dateformat/dateformat_parse.cpp
index b6e9f7c92eb6f..a82a20a42f969 100644
--- a/ext/intl/dateformat/dateformat_parse.c
+++ b/ext/intl/dateformat/dateformat_parse.cpp
@@ -19,8 +19,10 @@
 #include <unicode/ustring.h>
 #include <math.h>
 
+extern "C" {
 #include "php_intl.h"
 #include "intl_convert.h"
+}
 #include "dateformat.h"
 #include "dateformat_class.h"
 #include "dateformat_data.h"
@@ -70,7 +72,7 @@ static void internal_parse_to_timestamp(IntlDateFormatter_object *dfo, char* tex
 
 static void add_to_localtime_arr( IntlDateFormatter_object *dfo, zval* return_value, const UCalendar *parsed_calendar, zend_long calendar_field, char* key_name)
 {
-	zend_long calendar_field_val = ucal_get( parsed_calendar, calendar_field, &INTL_DATA_ERROR_CODE(dfo));
+	zend_long calendar_field_val = ucal_get( parsed_calendar, static_cast<UCalendarDateFields>(calendar_field), &INTL_DATA_ERROR_CODE(dfo));
 	INTL_METHOD_CHECK_STATUS( dfo, "Date parsing - localtime failed : could not get a field from calendar" );
 
 	if( strcmp(key_name, CALENDAR_YEAR )==0 ){
@@ -126,7 +128,7 @@ static void internal_parse_to_localtime(IntlDateFormatter_object *dfo, char* tex
 
 
 /* {{{ Parse the string $value starting at parse_pos to a Unix timestamp -int */
-PHP_FUNCTION(datefmt_parse)
+U_CFUNC PHP_FUNCTION(datefmt_parse)
 {
 	char*           text_to_parse = NULL;
 	size_t          text_len =0;
@@ -165,7 +167,7 @@ PHP_FUNCTION(datefmt_parse)
 }
 /* }}} */
 
-PHP_METHOD(IntlDateFormatter, parseToCalendar)
+U_CFUNC PHP_METHOD(IntlDateFormatter, parseToCalendar)
 {
 	zend_string *text_to_parse = NULL;
 	zval* z_parse_pos = NULL;
@@ -208,7 +210,7 @@ PHP_METHOD(IntlDateFormatter, parseToCalendar)
 }
 
 /* {{{ Parse the string $value to a localtime array */
-PHP_FUNCTION(datefmt_localtime)
+U_CFUNC PHP_FUNCTION(datefmt_localtime)
 {
 	char*           text_to_parse = NULL;
 	size_t          text_len =0;
diff --git a/ext/intl/formatter/formatter_attr.c b/ext/intl/formatter/formatter_attr.cpp
similarity index 86%
rename from ext/intl/formatter/formatter_attr.c
rename to ext/intl/formatter/formatter_attr.cpp
index a7cafcf5f9733..06f1023cc585e 100644
--- a/ext/intl/formatter/formatter_attr.c
+++ b/ext/intl/formatter/formatter_attr.cpp
@@ -16,25 +16,29 @@
 #include <config.h>
 #endif
 
+extern "C" {
 #include "php_intl.h"
-#include "formatter_class.h"
 #include "intl_convert.h"
+}
+#include "formatter_class.h"
 
 #include <unicode/ustring.h>
 
 /* {{{ Get formatter attribute value. */
-PHP_FUNCTION( numfmt_get_attribute )
+U_CFUNC PHP_FUNCTION( numfmt_get_attribute )
 {
-	zend_long attribute, value;
+	zend_long zattribute, value;
 	FORMATTER_METHOD_INIT_VARS;
 
 	/* Parse parameters. */
 	if( zend_parse_method_parameters( ZEND_NUM_ARGS(), getThis(), "Ol",
-		&object, NumberFormatter_ce_ptr, &attribute ) == FAILURE )
+		&object, NumberFormatter_ce_ptr, &zattribute ) == FAILURE )
 	{
 		RETURN_THROWS();
 	}
 
+	UNumberFormatAttribute attribute = static_cast<UNumberFormatAttribute>(zattribute);
+
 	/* Fetch the object. */
 	FORMATTER_METHOD_FETCH_OBJECT;
 
@@ -85,9 +89,9 @@ PHP_FUNCTION( numfmt_get_attribute )
 /* }}} */
 
 /* {{{ Get formatter attribute value. */
-PHP_FUNCTION( numfmt_get_text_attribute )
+U_CFUNC PHP_FUNCTION( numfmt_get_text_attribute )
 {
-	zend_long   attribute;
+	zend_long   zattribute;
 	UChar   value_buf[64];
 	int32_t value_buf_size = USIZE( value_buf );
 	UChar*  value  = value_buf;
@@ -96,7 +100,7 @@ PHP_FUNCTION( numfmt_get_text_attribute )
 
 	/* Parse parameters. */
 	if( zend_parse_method_parameters( ZEND_NUM_ARGS(), getThis(), "Ol",
-		&object, NumberFormatter_ce_ptr, &attribute ) == FAILURE )
+		&object, NumberFormatter_ce_ptr, &zattribute ) == FAILURE )
 	{
 		RETURN_THROWS();
 	}
@@ -104,6 +108,8 @@ PHP_FUNCTION( numfmt_get_text_attribute )
 	/* Fetch the object. */
 	FORMATTER_METHOD_FETCH_OBJECT;
 
+	UNumberFormatTextAttribute attribute = static_cast<UNumberFormatTextAttribute>(zattribute);
+
 	length = unum_getTextAttribute( FORMATTER_OBJECT(nfo), attribute, value, value_buf_size, &INTL_DATA_ERROR_CODE(nfo) );
 	if(INTL_DATA_ERROR_CODE(nfo) == U_BUFFER_OVERFLOW_ERROR && length >= value_buf_size) {
 		++length; /* to avoid U_STRING_NOT_TERMINATED_WARNING */
@@ -122,15 +128,15 @@ PHP_FUNCTION( numfmt_get_text_attribute )
 /* }}} */
 
 /* {{{ Get formatter attribute value. */
-PHP_FUNCTION( numfmt_set_attribute )
+U_CFUNC PHP_FUNCTION( numfmt_set_attribute )
 {
-	zend_long attribute;
+	zend_long zattribute;
 	zval *value;
 	FORMATTER_METHOD_INIT_VARS;
 
 	/* Parse parameters. */
 	if( zend_parse_method_parameters( ZEND_NUM_ARGS(), getThis(), "Oln",
-		&object, NumberFormatter_ce_ptr, &attribute, &value ) == FAILURE)
+		&object, NumberFormatter_ce_ptr, &zattribute, &value ) == FAILURE)
 	{
 		RETURN_THROWS();
 	}
@@ -138,6 +144,8 @@ PHP_FUNCTION( numfmt_set_attribute )
 	/* Fetch the object. */
 	FORMATTER_METHOD_FETCH_OBJECT;
 
+	UNumberFormatAttribute attribute = static_cast<UNumberFormatAttribute>(zattribute);
+
 	switch(attribute) {
 		case UNUM_PARSE_INT_ONLY:
 		case UNUM_GROUPING_USED:
@@ -175,7 +183,7 @@ PHP_FUNCTION( numfmt_set_attribute )
 /* }}} */
 
 /* {{{ Get formatter attribute value. */
-PHP_FUNCTION( numfmt_set_text_attribute )
+U_CFUNC PHP_FUNCTION( numfmt_set_text_attribute )
 {
 	int32_t slength = 0;
 	UChar *svalue = NULL;
@@ -199,7 +207,7 @@ PHP_FUNCTION( numfmt_set_text_attribute )
 	INTL_METHOD_CHECK_STATUS( nfo, "Error converting attribute value to UTF-16" );
 
 	/* Actually set new attribute value. */
-	unum_setTextAttribute(FORMATTER_OBJECT(nfo), attribute, svalue, slength, &INTL_DATA_ERROR_CODE(nfo));
+	unum_setTextAttribute(FORMATTER_OBJECT(nfo), static_cast<UNumberFormatTextAttribute>(attribute), svalue, slength, &INTL_DATA_ERROR_CODE(nfo));
 	if (svalue) {
 		efree(svalue);
 	}
@@ -210,9 +218,9 @@ PHP_FUNCTION( numfmt_set_text_attribute )
 /* }}} */
 
 /* {{{ Get formatter symbol value. */
-PHP_FUNCTION( numfmt_get_symbol )
+U_CFUNC PHP_FUNCTION( numfmt_get_symbol )
 {
-	zend_long symbol;
+	zend_long zsymbol;
 	UChar value_buf[4];
 	UChar *value = value_buf;
 	uint32_t length = USIZE(value_buf);
@@ -220,11 +228,13 @@ PHP_FUNCTION( numfmt_get_symbol )
 
 	/* Parse parameters. */
 	if( zend_parse_method_parameters( ZEND_NUM_ARGS(), getThis(), "Ol",
-		&object, NumberFormatter_ce_ptr, &symbol ) == FAILURE )
+		&object, NumberFormatter_ce_ptr, &zsymbol ) == FAILURE )
 	{
 		RETURN_THROWS();
 	}
 
+	UNumberFormatSymbol symbol = static_cast<UNumberFormatSymbol>(zsymbol);
+
 	if(symbol >= UNUM_FORMAT_SYMBOL_COUNT || symbol < 0) {
 		intl_error_set( NULL, U_ILLEGAL_ARGUMENT_ERROR,	"invalid symbol value");
 		RETURN_FALSE;
@@ -251,9 +261,9 @@ PHP_FUNCTION( numfmt_get_symbol )
 /* }}} */
 
 /* {{{ Set formatter symbol value. */
-PHP_FUNCTION( numfmt_set_symbol )
+U_CFUNC PHP_FUNCTION( numfmt_set_symbol )
 {
-	zend_long  symbol;
+	zend_long  zsymbol;
 	char*      value     = NULL;
 	size_t     value_len = 0;
 	UChar*     svalue  = 0;
@@ -262,11 +272,13 @@ PHP_FUNCTION( numfmt_set_symbol )
 
 	/* Parse parameters. */
 	if( zend_parse_method_parameters( ZEND_NUM_ARGS(), getThis(), "Ols",
-		&object, NumberFormatter_ce_ptr, &symbol, &value, &value_len ) == FAILURE )
+		&object, NumberFormatter_ce_ptr, &zsymbol, &value, &value_len ) == FAILURE )
 	{
 		RETURN_THROWS();
 	}
 
+	UNumberFormatSymbol symbol = static_cast<UNumberFormatSymbol>(zsymbol);
+
 	if (symbol >= UNUM_FORMAT_SYMBOL_COUNT || symbol < 0) {
 		intl_error_set( NULL, U_ILLEGAL_ARGUMENT_ERROR,	"invalid symbol value");
 		RETURN_FALSE;
@@ -291,7 +303,7 @@ PHP_FUNCTION( numfmt_set_symbol )
 /* }}} */
 
 /* {{{ Get formatter pattern. */
-PHP_FUNCTION( numfmt_get_pattern )
+U_CFUNC PHP_FUNCTION( numfmt_get_pattern )
 {
 	UChar   value_buf[64];
 	uint32_t length = USIZE( value_buf );
@@ -326,7 +338,7 @@ PHP_FUNCTION( numfmt_get_pattern )
 /* }}} */
 
 /* {{{ Set formatter pattern. */
-PHP_FUNCTION( numfmt_set_pattern )
+U_CFUNC PHP_FUNCTION( numfmt_set_pattern )
 {
 	char*       value = NULL;
 	size_t      value_len = 0;
@@ -365,7 +377,7 @@ PHP_FUNCTION( numfmt_set_pattern )
 /* }}} */
 
 /* {{{ Get formatter locale. */
-PHP_FUNCTION( numfmt_get_locale )
+U_CFUNC PHP_FUNCTION( numfmt_get_locale )
 {
 	zend_long type = ULOC_ACTUAL_LOCALE;
 	char* loc;
@@ -381,7 +393,7 @@ PHP_FUNCTION( numfmt_get_locale )
 	/* Fetch the object. */
 	FORMATTER_METHOD_FETCH_OBJECT;
 
-	loc = (char *)unum_getLocaleByType(FORMATTER_OBJECT(nfo), type, &INTL_DATA_ERROR_CODE(nfo));
+	loc = (char *)unum_getLocaleByType(FORMATTER_OBJECT(nfo), static_cast<ULocDataLocaleType>(type), &INTL_DATA_ERROR_CODE(nfo));
 	INTL_METHOD_CHECK_STATUS( nfo, "Error getting locale" );
 	RETURN_STRING(loc);
 }
diff --git a/ext/intl/formatter/formatter_class.h b/ext/intl/formatter/formatter_class.h
index f7da2b2201917..aae6131205e3c 100644
--- a/ext/intl/formatter/formatter_class.h
+++ b/ext/intl/formatter/formatter_class.h
@@ -17,9 +17,15 @@
 
 #include <php.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
 #include "intl_common.h"
 #include "intl_error.h"
 #include "intl_data.h"
+#ifdef __cplusplus
+}
+#endif
 #include "formatter_data.h"
 
 typedef struct {
@@ -32,8 +38,14 @@ static inline NumberFormatter_object *php_intl_number_format_fetch_object(zend_o
 }
 #define Z_INTL_NUMBERFORMATTER_P(zv) php_intl_number_format_fetch_object(Z_OBJ_P(zv))
 
+#ifdef __cplusplus
+extern "C" {
+#endif
 void formatter_register_class( void );
 extern zend_class_entry *NumberFormatter_ce_ptr;
+#ifdef __cplusplus
+}
+#endif
 
 /* Auxiliary macros */
 
diff --git a/ext/intl/formatter/formatter_data.c b/ext/intl/formatter/formatter_data.cpp
similarity index 94%
rename from ext/intl/formatter/formatter_data.c
rename to ext/intl/formatter/formatter_data.cpp
index 57dbc8bde6b5e..095be92ed29e1 100644
--- a/ext/intl/formatter/formatter_data.c
+++ b/ext/intl/formatter/formatter_data.cpp
@@ -52,7 +52,7 @@ void formatter_data_free( formatter_data* nf_data )
  */
 formatter_data* formatter_data_create( void )
 {
-	formatter_data* nf_data = ecalloc( 1, sizeof(formatter_data) );
+	formatter_data* nf_data = reinterpret_cast<formatter_data *>(ecalloc( 1, sizeof(formatter_data) ));
 
 	formatter_data_init( nf_data );
 
diff --git a/ext/intl/formatter/formatter_data.h b/ext/intl/formatter/formatter_data.h
index 817ad0d6055f3..35acc242a8db9 100644
--- a/ext/intl/formatter/formatter_data.h
+++ b/ext/intl/formatter/formatter_data.h
@@ -19,7 +19,13 @@
 
 #include <unicode/unum.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
 #include "intl_error.h"
+#ifdef __cplusplus
+}
+#endif
 
 typedef struct {
 	// error hangling
@@ -29,8 +35,14 @@ typedef struct {
 	UNumberFormat*  unum;
 } formatter_data;
 
+#ifdef __cplusplus
+extern "C" {
+#endif
 formatter_data* formatter_data_create( void );
 void formatter_data_init( formatter_data* nf_data );
 void formatter_data_free( formatter_data* nf_data );
+#ifdef __cplusplus
+}
+#endif
 
 #endif // FORMATTER_DATA_H
diff --git a/ext/intl/formatter/formatter_format.c b/ext/intl/formatter/formatter_format.cpp
similarity index 98%
rename from ext/intl/formatter/formatter_format.c
rename to ext/intl/formatter/formatter_format.cpp
index 5be732dde77e8..f28ea30b9ff8f 100644
--- a/ext/intl/formatter/formatter_format.c
+++ b/ext/intl/formatter/formatter_format.cpp
@@ -16,16 +16,18 @@
 #include <config.h>
 #endif
 
+extern "C" {
 #include "php_intl.h"
+#include "intl_convert.h"
+}
 
 #include <unicode/ustring.h>
 
 #include "formatter_class.h"
 #include "formatter_format.h"
-#include "intl_convert.h"
 
 /* {{{ Format a number. */
-PHP_FUNCTION( numfmt_format )
+U_CFUNC PHP_FUNCTION( numfmt_format )
 {
 	zval *number;
 	zend_long type = FORMAT_TYPE_DEFAULT;
@@ -123,7 +125,7 @@ PHP_FUNCTION( numfmt_format )
 /* }}} */
 
 /* {{{ Format a number as currency. */
-PHP_FUNCTION( numfmt_format_currency )
+U_CFUNC PHP_FUNCTION( numfmt_format_currency )
 {
 	double     number;
 	UChar      format_buf[32];
diff --git a/ext/intl/formatter/formatter_main.c b/ext/intl/formatter/formatter_main.cpp
similarity index 91%
rename from ext/intl/formatter/formatter_main.c
rename to ext/intl/formatter/formatter_main.cpp
index 6f92b7e787be4..e8bb743f18d07 100644
--- a/ext/intl/formatter/formatter_main.c
+++ b/ext/intl/formatter/formatter_main.cpp
@@ -19,9 +19,11 @@
 #include <unicode/ustring.h>
 #include <unicode/uloc.h>
 
+extern "C" {
 #include "php_intl.h"
-#include "formatter_class.h"
 #include "intl_convert.h"
+}
+#include "formatter_class.h"
 
 /* {{{ */
 static int numfmt_ctor(INTERNAL_FUNCTION_PARAMETERS)
@@ -65,7 +67,7 @@ static int numfmt_ctor(INTERNAL_FUNCTION_PARAMETERS)
 	}
 
 	/* Create an ICU number formatter. */
-	FORMATTER_OBJECT(nfo) = unum_open(style, spattern, spattern_len, locale, NULL, &INTL_DATA_ERROR_CODE(nfo));
+	FORMATTER_OBJECT(nfo) = unum_open(static_cast<UNumberFormatStyle>(style), spattern, spattern_len, locale, NULL, &INTL_DATA_ERROR_CODE(nfo));
 
 	if(spattern) {
 		efree(spattern);
@@ -77,7 +79,7 @@ static int numfmt_ctor(INTERNAL_FUNCTION_PARAMETERS)
 /* }}} */
 
 /* {{{ Create number formatter. */
-PHP_FUNCTION( numfmt_create )
+U_CFUNC PHP_FUNCTION( numfmt_create )
 {
 	object_init_ex( return_value, NumberFormatter_ce_ptr );
 	if (numfmt_ctor(INTERNAL_FUNCTION_PARAM_PASSTHRU) == FAILURE) {
@@ -88,7 +90,7 @@ PHP_FUNCTION( numfmt_create )
 /* }}} */
 
 /* {{{ NumberFormatter object constructor. */
-PHP_METHOD( NumberFormatter, __construct )
+U_CFUNC PHP_METHOD( NumberFormatter, __construct )
 {
 	const bool old_use_exception = INTL_G(use_exceptions);
 	const zend_long old_error_level = INTL_G(error_level);
@@ -105,7 +107,7 @@ PHP_METHOD( NumberFormatter, __construct )
 /* }}} */
 
 /* {{{ Get formatter's last error code. */
-PHP_FUNCTION( numfmt_get_error_code )
+U_CFUNC PHP_FUNCTION( numfmt_get_error_code )
 {
 	FORMATTER_METHOD_INIT_VARS
 
@@ -124,7 +126,7 @@ PHP_FUNCTION( numfmt_get_error_code )
 /* }}} */
 
 /* {{{ Get text description for formatter's last error code. */
-PHP_FUNCTION( numfmt_get_error_message )
+U_CFUNC PHP_FUNCTION( numfmt_get_error_message )
 {
 	zend_string *message = NULL;
 	FORMATTER_METHOD_INIT_VARS
diff --git a/ext/intl/formatter/formatter_parse.c b/ext/intl/formatter/formatter_parse.cpp
similarity index 98%
rename from ext/intl/formatter/formatter_parse.c
rename to ext/intl/formatter/formatter_parse.cpp
index ba8307419b4cf..c7d0df8cbda02 100644
--- a/ext/intl/formatter/formatter_parse.c
+++ b/ext/intl/formatter/formatter_parse.cpp
@@ -16,19 +16,21 @@
 #include <config.h>
 #endif
 
+extern "C" {
 #include "php_intl.h"
+#include "intl_convert.h"
+}
 
 #include <unicode/ustring.h>
 #include <locale.h>
 
 #include "formatter_class.h"
 #include "formatter_format.h"
-#include "intl_convert.h"
 
 #define ICU_LOCALE_BUG 1
 
 /* {{{ Parse a number. */
-PHP_FUNCTION( numfmt_parse )
+U_CFUNC PHP_FUNCTION( numfmt_parse )
 {
 	zend_long type = FORMAT_TYPE_DOUBLE;
 	UChar* sstr = NULL;
@@ -120,7 +122,7 @@ PHP_FUNCTION( numfmt_parse )
 /* }}} */
 
 /* {{{ Parse a number as currency. */
-PHP_FUNCTION( numfmt_parse_currency )
+U_CFUNC PHP_FUNCTION( numfmt_parse_currency )
 {
 	double number;
 	UChar currency[5] = {0};