It's a tradition return NULL on error of args parsing

ext/mbstring/mbstring.c

@@ -1739,7 +1739,7 @@ PHP_FUNCTION(mb_internal_encoding)
 	const mbfl_encoding *encoding;
 
 	if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "|s", &name, &name_len) == FAILURE) {
-		RETURN_FALSE;
+		return;
 	}
 	if (name == NULL) {
 		name = MBSTRG(current_internal_encoding) ? MBSTRG(current_internal_encoding)->name: NULL;
@@ -1773,7 +1773,7 @@ PHP_FUNCTION(mb_http_input)
 
 	retname = 1;
  	if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "|s", &typ, &typ_len) == FAILURE) {
- 		RETURN_FALSE;
+		return;
  	}
  	if (typ == NULL) {
  		result = MBSTRG(http_input_identify);
@@ -2196,7 +2196,7 @@ PHP_FUNCTION(mb_strlen)
 	mbfl_string_init(&string);
 
 	if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "s|s", (char **)&string.val, &string.len, &enc_name, &enc_name_len) == FAILURE) {
-		RETURN_FALSE;
+		return;
 	}
 
 	string.no_language = MBSTRG(language);
@@ -2394,7 +2394,7 @@ PHP_FUNCTION(mb_stripos)
 	offset = 0;
 
 	if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "ss|ls", (char **)&haystack.val, (int *)&haystack.len, (char **)&needle.val, (int *)&needle.len, &offset, &from_encoding, &from_encoding_len) == FAILURE) {
-		RETURN_FALSE;
+		return;
 	}
 	if (needle.len == 0) {
 		php_error_docref(NULL TSRMLS_CC, E_WARNING, "Empty delimiter");
@@ -2423,7 +2423,7 @@ PHP_FUNCTION(mb_strripos)
 	offset = 0;
 
 	if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "ss|ls", (char **)&haystack.val, (int *)&haystack.len, (char **)&needle.val, (int *)&needle.len, &offset, &from_encoding, &from_encoding_len) == FAILURE) {
-		RETURN_FALSE;
+		return;
 	}
 
 	n = php_mb_stripos(1, (char *)haystack.val, haystack.len, (char *)needle.val, needle.len, offset, from_encoding TSRMLS_CC);
@@ -2454,7 +2454,7 @@ PHP_FUNCTION(mb_strstr)
 	needle.no_encoding = MBSTRG(current_internal_encoding)->no_encoding;
 
 	if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "ss|bs", (char **)&haystack.val, (int *)&haystack.len, (char **)&needle.val, (int *)&needle.len, &part, &enc_name, &enc_name_len) == FAILURE) {
-		RETURN_FALSE;
+		return;
 	}
 
 	if (enc_name != NULL) {
@@ -2516,7 +2516,7 @@ PHP_FUNCTION(mb_strrchr)
 	needle.no_encoding = MBSTRG(current_internal_encoding)->no_encoding;
 
 	if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "ss|bs", (char **)&haystack.val, &haystack.len, (char **)&needle.val, &needle.len, &part, &enc_name, &enc_name_len) == FAILURE) {
-		RETURN_FALSE;
+		return;
 	}
 
 	if (enc_name != NULL) {
@@ -2580,7 +2580,7 @@ PHP_FUNCTION(mb_stristr)
 
 
 	if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "ss|bs", (char **)&haystack.val, &haystack.len, (char **)&needle.val, &needle.len, &part, &from_encoding, &from_encoding_len) == FAILURE) {
-		RETURN_FALSE;
+		return;
 	}
 
 	if (!needle.len) {
@@ -2642,7 +2642,7 @@ PHP_FUNCTION(mb_strrichr)
 
 
 	if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "ss|bs", (char **)&haystack.val, &haystack.len, (char **)&needle.val, &needle.len, &part, &from_encoding, &from_encoding_len) == FAILURE) {
-		RETURN_FALSE;
+		return;
 	}
 
 	haystack.no_encoding = needle.no_encoding = mbfl_name2no_encoding(from_encoding);
@@ -3142,8 +3142,9 @@ PHP_FUNCTION(mb_convert_case)
 
 	RETVAL_FALSE;
 	if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "sl|s!", &str, &str_len,
-				&case_mode, &from_encoding, &from_encoding_len) == FAILURE)
-		RETURN_FALSE;
+				&case_mode, &from_encoding, &from_encoding_len) == FAILURE) {
+		return;
+	}
 
 	newstr = php_unicode_convert_case(case_mode, str, (size_t) str_len, &ret_len, from_encoding TSRMLS_CC);
 
@@ -3312,7 +3313,7 @@ PHP_FUNCTION(mb_encoding_aliases)
 	int name_len;
 
 	if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "s", &name, &name_len) == FAILURE) {
-		RETURN_FALSE;
+		return;
 	}
 
 	encoding = mbfl_name2encoding(name);
@@ -4537,7 +4538,7 @@ PHP_FUNCTION(mb_check_encoding)
 	long illegalchars = 0;
 
 	if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "|ss", &var, &var_len, &enc, &enc_len) == FAILURE) {
-		RETURN_FALSE;
+		return;
 	}
 
 	if (var == NULL) {

ext/mbstring/tests/mb_internal_encoding_error1.phpt

@@ -32,5 +32,5 @@ echo "Done";
 -- Testing mb_internal_encoding() function with more than expected no. of arguments --
 
 Warning: mb_internal_encoding() expects at most 1 parameter, 2 given in %s on line %d
-bool(false)
+NULL
 Done

ext/mbstring/tests/mb_internal_encoding_variation1.phpt

@@ -213,5 +213,5 @@ bool(false)
 -- Iteration 24 --
 
 Warning: mb_internal_encoding() expects parameter 1 to be string, resource given in %s on line %d
-bool(false)
+NULL
 Done

ext/mbstring/tests/mb_stripos.phpt

@@ -106,13 +106,13 @@ $r = mb_stripos($euc_jp,b"\n");
 echo "== INVALID PARAMETER TEST ==\n";
 
 $r = mb_stripos($euc_jp,'','EUC-JP');
-($r === FALSE) ? print("OK_NULL\n") : print("NG_NULL\n");
+($r === NULL) ? print("OK_NULL\n") : print("NG_NULL\n");
 $r = mb_stripos($euc_jp, $t_ary, 'EUC-JP');
-($r === FALSE) ? print("OK_ARRAY\n") : print("NG_ARRAY\n");
+($r === NULL) ? print("OK_ARRAY\n") : print("NG_ARRAY\n");
 $r = mb_stripos($euc_jp, $t_obj, 'EUC-JP');
-($r === FALSE) ? print("OK_OBJECT\n") : print("NG_OBJECT\n");
+($r === NULL) ? print("OK_OBJECT\n") : print("NG_OBJECT\n");
 $r = mb_stripos($euc_jp, $t_obj, 'BAD_ENCODING');
-($r === FALSE) ? print("OK_BAD_ENCODING\n") : print("NG_BAD_ENCODING\n");
+($r === NULL) ? print("OK_BAD_ENCODING\n") : print("NG_BAD_ENCODING\n");
 
 
 ?>

ext/mbstring/tests/mb_stripos_error1.phpt

@@ -42,10 +42,10 @@ echo "Done";
 -- Testing mb_stripos() function with more than expected no. of arguments --
 
 Warning: mb_stripos() expects at most 4 parameters, 5 given in %s on line %d
-bool(false)
+NULL
 
 -- Testing mb_stripos() function with less than expected no. of arguments --
 
 Warning: mb_stripos() expects at least 2 parameters, 1 given in %s on line %d
-bool(false)
+NULL
 Done

ext/mbstring/tests/mb_stripos_variation1.phpt

@@ -179,5 +179,5 @@ bool(false)
 -- Iteration 24 --
 
 Warning: mb_stripos() expects parameter 1 to be string, resource given in %s on line %d
-bool(false)
-Done
+NULL
+Done

ext/mbstring/tests/mb_stripos_variation2.phpt

@@ -195,6 +195,6 @@ bool(false)
 -- Iteration 24 --
 
 Warning: mb_stripos() expects parameter 2 to be string, resource given in %s on line %d
-bool(false)
+NULL
 Done
 

ext/mbstring/tests/mb_stripos_variation3.phpt

@@ -163,32 +163,32 @@ int(8)
 -- Iteration 16 --
 
 Warning: mb_stripos() expects parameter 3 to be long, string given in %s on line %d
-bool(false)
+NULL
 
 -- Iteration 17 --
 
 Warning: mb_stripos() expects parameter 3 to be long, string given in %s on line %d
-bool(false)
+NULL
 
 -- Iteration 18 --
 
 Warning: mb_stripos() expects parameter 3 to be long, string given in %s on line %d
-bool(false)
+NULL
 
 -- Iteration 19 --
 
 Warning: mb_stripos() expects parameter 3 to be long, string given in %s on line %d
-bool(false)
+NULL
 
 -- Iteration 20 --
 
 Warning: mb_stripos() expects parameter 3 to be long, string given in %s on line %d
-bool(false)
+NULL
 
 -- Iteration 21 --
 
 Warning: mb_stripos() expects parameter 3 to be long, object given in %s on line %d
-bool(false)
+NULL
 
 -- Iteration 22 --
 int(8)
@@ -199,5 +199,5 @@ int(8)
 -- Iteration 24 --
 
 Warning: mb_stripos() expects parameter 3 to be long, resource given in %s on line %d
-bool(false)
+NULL
 Done

ext/mbstring/tests/mb_stripos_variation4.phpt

@@ -219,5 +219,5 @@ bool(false)
 -- Iteration 24 --
 
 Warning: mb_stripos() expects parameter 4 to be string, resource given in %s on line %d
-bool(false)
-Done
+NULL
+Done

ext/mbstring/tests/mb_stristr_error1.phpt

@@ -38,10 +38,10 @@ var_dump( mb_stristr($haystack) );
 -- Testing mb_stristr() function with more than expected no. of arguments --
 
 Warning: mb_stristr() expects at most 4 parameters, 5 given in %s on line %d
-bool(false)
+NULL
 
 -- Testing mb_stristr() function with less than expected no. of arguments --
 
 Warning: mb_stristr() expects at least 2 parameters, 1 given in %s on line %d
-bool(false)
+NULL
 ===DONE===

ext/mbstring/tests/mb_stristr_variation1.phpt

@@ -150,19 +150,19 @@ bool(false)
 
 --empty array--
 Error: 2 - mb_stristr() expects parameter 1 to be string, array given, %s(%d)
-bool(false)
+NULL
 
 --int indexed array--
 Error: 2 - mb_stristr() expects parameter 1 to be string, array given, %s(%d)
-bool(false)
+NULL
 
 --associative array--
 Error: 2 - mb_stristr() expects parameter 1 to be string, array given, %s(%d)
-bool(false)
+NULL
 
 --nested arrays--
 Error: 2 - mb_stristr() expects parameter 1 to be string, array given, %s(%d)
-bool(false)
+NULL
 
 --uppercase NULL--
 bool(false)
@@ -193,7 +193,7 @@ bool(false)
 
 --instance of classWithoutToString--
 Error: 2 - mb_stristr() expects parameter 1 to be string, object given, %s(%d)
-bool(false)
+NULL
 
 --undefined var--
 bool(false)
@@ -203,6 +203,6 @@ bool(false)
 
 --resource--
 Error: 2 - mb_stristr() expects parameter 1 to be string, resource given, %s(%d)
-bool(false)
+NULL
 ===DONE===
 

ext/mbstring/tests/mb_stristr_variation2.phpt

@@ -150,19 +150,19 @@ bool(false)
 
 --empty array--
 Error: 2 - mb_stristr() expects parameter 2 to be string, array given, %s(%d)
-bool(false)
+NULL
 
 --int indexed array--
 Error: 2 - mb_stristr() expects parameter 2 to be string, array given, %s(%d)
-bool(false)
+NULL
 
 --associative array--
 Error: 2 - mb_stristr() expects parameter 2 to be string, array given, %s(%d)
-bool(false)
+NULL
 
 --nested arrays--
 Error: 2 - mb_stristr() expects parameter 2 to be string, array given, %s(%d)
-bool(false)
+NULL
 
 --uppercase NULL--
 Error: 2 - mb_stristr(): Empty delimiter, %s(%d)
@@ -199,7 +199,7 @@ bool(false)
 
 --instance of classWithoutToString--
 Error: 2 - mb_stristr() expects parameter 2 to be string, object given, %s(%d)
-bool(false)
+NULL
 
 --undefined var--
 Error: 2 - mb_stristr(): Empty delimiter, %s(%d)
@@ -211,6 +211,6 @@ bool(false)
 
 --resource--
 Error: 2 - mb_stristr() expects parameter 2 to be string, resource given, %s(%d)
-bool(false)
+NULL
 ===DONE===
 

ext/mbstring/tests/mb_stristr_variation3.phpt

@@ -118,7 +118,7 @@ $inputs = array(
 foreach($inputs as $key =>$value) {
       echo "\n--$key--\n";
       $res = mb_stristr($haystack, $needle, $value, $encoding);
-      if ($res === false) {
+      if ($res === NULL) {
          var_dump($res);
       }
       else {
@@ -162,19 +162,19 @@ string(12) "737472696e67"
 
 --empty array--
 Error: 2 - mb_stristr() expects parameter 3 to be boolean, array given, %s(%d)
-bool(false)
+NULL
 
 --int indexed array--
 Error: 2 - mb_stristr() expects parameter 3 to be boolean, array given, %s(%d)
-bool(false)
+NULL
 
 --associative array--
 Error: 2 - mb_stristr() expects parameter 3 to be boolean, array given, %s(%d)
-bool(false)
+NULL
 
 --nested arrays--
 Error: 2 - mb_stristr() expects parameter 3 to be boolean, array given, %s(%d)
-bool(false)
+NULL
 
 --uppercase NULL--
 string(8) "5f76616c"
@@ -214,11 +214,11 @@ string(12) "737472696e67"
 
 --instance of classWithToString--
 Error: 2 - mb_stristr() expects parameter 3 to be boolean, object given, %s(%d)
-bool(false)
+NULL
 
 --instance of classWithoutToString--
 Error: 2 - mb_stristr() expects parameter 3 to be boolean, object given, %s(%d)
-bool(false)
+NULL
 
 --undefined var--
 string(8) "5f76616c"
@@ -228,5 +228,5 @@ string(8) "5f76616c"
 
 --resource--
 Error: 2 - mb_stristr() expects parameter 3 to be boolean, resource given, %s(%d)
-bool(false)
+NULL
 ===DONE===