diff --git a/.gitignore b/.gitignore
index ec831ee..bbec32a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -7,6 +7,7 @@ config.guess
 config.h.in
 config.h.in~
 config.sub
+configure~
 configure
 configure.in
 configure.ac
diff --git a/package.xml b/package.xml
index eaaf18d..7e62416 100644
--- a/package.xml
+++ b/package.xml
@@ -42,6 +42,7 @@ more than adequate.
  <license uri="https://www.php.net/license/3_01.txt" filesource="LICENSE">PHP-3.01</license>
  <notes>
 - drop PHP 5 support
+- add type hinting with PHP 8+
  </notes>
  <contents>
   <dir name="/">
@@ -65,6 +66,9 @@ more than adequate.
    <file name="config.w32" role="src" />
    <dir name="src">
     <file name="dio.c" role="src" />
+    <file name="dio.stub.php" role="src" />
+    <file name="dio_arginfo.h" role="src" />
+    <file name="dio_legacy_arginfo.h" role="src" />
     <file name="dio_common.c" role="src" />
     <file name="dio_posix.c" role="src" />
     <file name="dio_win32.c" role="src" />
diff --git a/src/dio.c b/src/dio.c
index ba10124..6a476aa 100644
--- a/src/dio.c
+++ b/src/dio.c
@@ -47,6 +47,11 @@
 # endif /* CNEW_RTSCTS */
 #endif /* !CRTSCTS */
 
+#if PHP_VERSION_ID < 80000
+#include "dio_legacy_arginfo.h"
+#else
+#include "dio_arginfo.h"
+#endif
 /*
    +----------------------------------------------------------------------+
    |                       DEPRECATED FUNCTIONALITY                       |
@@ -738,116 +743,16 @@ static void dio_init_legacy_defines(int module_number) {
 #endif
 }
 
-ZEND_BEGIN_ARG_INFO_EX(dio_open_args, 0, 0, 2)
-	ZEND_ARG_INFO(0, filename)
-	ZEND_ARG_INFO(0, flags)
-	ZEND_ARG_INFO(0, mode)
-ZEND_END_ARG_INFO()
-
-ZEND_BEGIN_ARG_INFO_EX(dio_fdopen_args, 0, 0, 1)
-	ZEND_ARG_INFO(0, fd)
-ZEND_END_ARG_INFO()
-
-ZEND_BEGIN_ARG_INFO_EX(dio_dup_args, 0, 0, 1)
-	ZEND_ARG_INFO(0, fd)
-ZEND_END_ARG_INFO()
-
-
-ZEND_BEGIN_ARG_INFO_EX(dio_read_args, 0, 0, 1)
-	ZEND_ARG_INFO(0, fd)
-	ZEND_ARG_INFO(0, n)
-ZEND_END_ARG_INFO()
-
-ZEND_BEGIN_ARG_INFO_EX(dio_write_args, 0, 0, 2)
-	ZEND_ARG_INFO(0, fd)
-	ZEND_ARG_INFO(0, data)
-	ZEND_ARG_INFO(0, len)
-ZEND_END_ARG_INFO()
-
-ZEND_BEGIN_ARG_INFO_EX(dio_stat_args, 0, 0, 1)
-	ZEND_ARG_INFO(0, fd)
-ZEND_END_ARG_INFO()
-
-ZEND_BEGIN_ARG_INFO_EX(dio_truncate_args, 0, 0, 2)
-	ZEND_ARG_INFO(0, fd)
-	ZEND_ARG_INFO(0, offset)
-ZEND_END_ARG_INFO()
-
-ZEND_BEGIN_ARG_INFO_EX(dio_seek_args, 0, 0, 3)
-	ZEND_ARG_INFO(0, fd)
-	ZEND_ARG_INFO(0, pos)
-	ZEND_ARG_INFO(0, whence)
-ZEND_END_ARG_INFO()
-
-ZEND_BEGIN_ARG_INFO_EX(dio_fcntl_args, 0, 0, 2)
-	ZEND_ARG_INFO(0, fd)
-	ZEND_ARG_INFO(0, cmd)
-	ZEND_ARG_INFO(0, arg)
-ZEND_END_ARG_INFO()
-
-ZEND_BEGIN_ARG_INFO_EX(dio_tcsetattr_args, 0, 0, 2)
-	ZEND_ARG_INFO(0, fd)
-	ZEND_ARG_INFO(0, args)
-ZEND_END_ARG_INFO()
-
-ZEND_BEGIN_ARG_INFO_EX(dio_close_args, 0, 0, 1)
-	ZEND_ARG_INFO(0, fd)
-ZEND_END_ARG_INFO()
-
 /*
    +----------------------------------------------------------------------+
    |                   END OF DEPRECATED FUNCTIONALITY                    |
    +----------------------------------------------------------------------+
  */
 
-ZEND_BEGIN_ARG_INFO_EX(dio_raw_args, 0, 0, 2)
-	ZEND_ARG_INFO(0, filename)
-	ZEND_ARG_INFO(0, mode)
-	ZEND_ARG_INFO(0, options)
-ZEND_END_ARG_INFO()
-
-ZEND_BEGIN_ARG_INFO_EX(dio_serial_args, 0, 0, 2)
-	ZEND_ARG_INFO(0, filename)
-	ZEND_ARG_INFO(0, mode)
-	ZEND_ARG_INFO(0, options)
-ZEND_END_ARG_INFO()
-
-/* not used static zend_object_handlers dio_raw_object_handlers; */
-
-static zend_function_entry dio_functions[] = {
-	/* Class functions. */
-
-	/* Legacy functions (Deprecated - See dio_legacy.c) */
-	PHP_FE(dio_open, dio_open_args)
-#ifndef PHP_WIN32
-	PHP_FE(dio_fdopen, dio_fdopen_args)
-	PHP_FE(dio_dup, dio_dup_args)
-	PHP_FE(dio_truncate, dio_truncate_args)
-#endif
-	PHP_FE(dio_stat, dio_stat_args)
-	PHP_FE(dio_seek, dio_seek_args)
-#ifndef PHP_WIN32
-	PHP_FE(dio_fcntl, dio_fcntl_args)
-#endif
-	PHP_FE(dio_read, dio_read_args)
-	PHP_FE(dio_write, dio_write_args)
-	PHP_FE(dio_close, dio_close_args)
-#ifndef PHP_WIN32
-	PHP_FE(dio_tcsetattr, dio_tcsetattr_args)
-#endif
-
-	/* Stream functions */
-	PHP_FE(dio_raw, dio_raw_args)
-	PHP_FE(dio_serial, dio_serial_args)
-
-	/* End of functions */
-	{NULL, NULL, NULL}
-};
-
 zend_module_entry dio_module_entry = {
 	STANDARD_MODULE_HEADER,
 	"dio",
-	dio_functions,
+	ext_functions,
 	PHP_MINIT(dio),
 	NULL,
 	NULL,	
diff --git a/src/dio.stub.php b/src/dio.stub.php
new file mode 100644
index 0000000..90a24cc
--- /dev/null
+++ b/src/dio.stub.php
@@ -0,0 +1,84 @@
+<?php
+
+/** 
+ * @generate-class-entries
+ * @generate-legacy-arginfo
+ */
+
+/**
+ * @return resource|false
+ */
+function dio_open(string $filename, int $flags, int $mode=0) {}
+
+#ifndef PHP_WIN32
+/**
+ * @param resource $fd
+ * @return resource|false
+ */
+function dio_fdopen($fd) {}
+
+/**
+ * @param resource $fd
+ * @return resource|false
+ */
+function dio_dup($fd) {}
+
+/**
+ * @param resource $fd
+ */
+function dio_truncate($fd, int $offset): bool {}
+#endif
+
+/**
+ * @param resource $fd
+ */
+function dio_stat($fd): array|false {}
+
+/**
+ * @param resource $fd
+ */
+function dio_seek($fd, int $pos, int $whence=SEEK_SET): int|false {}
+
+#ifndef PHP_WIN32
+/**
+ * @param resource $fd
+ * @param mixed $arg
+ * @return mixed
+ */
+function dio_fcntl($fd, int $cmd, $arg=NULL) {}
+#endif
+
+/**
+ * @param resource $fd
+ */
+function dio_read($fd, int $n=1024): int|null|false {}
+
+/**
+ * @param resource $fd
+ */
+function dio_write($fd, string $data, int $len=0): int|false {}
+
+/**
+ * @param resource $fd
+ */
+function dio_close($fd): null|false {}
+
+#ifndef PHP_WIN32
+/**
+ * @param resource $fd
+ * @param mixed $arg
+ * @return mixed
+ */
+function dio_tcsetattr($fd, array $args): bool {}
+#endif
+
+/**
+ * @return resource|false
+ */
+function dio_raw(string $filename, string $mode, ?array $options=NULL) {}
+
+/**
+ * @return resource|false
+ */
+function dio_serial(string $filename, string $mode, ?array $options=NULL) {}
+
diff --git a/src/dio_arginfo.h b/src/dio_arginfo.h
new file mode 100644
index 0000000..8484ae7
--- /dev/null
+++ b/src/dio_arginfo.h
@@ -0,0 +1,126 @@
+/* This is a generated file, edit the .stub.php file instead.
+ * Stub hash: 74f93c791a08145405f1f08b0d8ee26876e92798 */
+
+ZEND_BEGIN_ARG_INFO_EX(arginfo_dio_open, 0, 0, 2)
+	ZEND_ARG_TYPE_INFO(0, filename, IS_STRING, 0)
+	ZEND_ARG_TYPE_INFO(0, flags, IS_LONG, 0)
+	ZEND_ARG_TYPE_INFO_WITH_DEFAULT_VALUE(0, mode, IS_LONG, 0, "0")
+ZEND_END_ARG_INFO()
+
+#if !defined(PHP_WIN32)
+ZEND_BEGIN_ARG_INFO_EX(arginfo_dio_fdopen, 0, 0, 1)
+	ZEND_ARG_INFO(0, fd)
+ZEND_END_ARG_INFO()
+#endif
+
+#if !defined(PHP_WIN32)
+#define arginfo_dio_dup arginfo_dio_fdopen
+#endif
+
+#if !defined(PHP_WIN32)
+ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX(arginfo_dio_truncate, 0, 2, _IS_BOOL, 0)
+	ZEND_ARG_INFO(0, fd)
+	ZEND_ARG_TYPE_INFO(0, offset, IS_LONG, 0)
+ZEND_END_ARG_INFO()
+#endif
+
+ZEND_BEGIN_ARG_WITH_RETURN_TYPE_MASK_EX(arginfo_dio_stat, 0, 1, MAY_BE_ARRAY|MAY_BE_FALSE)
+	ZEND_ARG_INFO(0, fd)
+ZEND_END_ARG_INFO()
+
+ZEND_BEGIN_ARG_WITH_RETURN_TYPE_MASK_EX(arginfo_dio_seek, 0, 2, MAY_BE_LONG|MAY_BE_FALSE)
+	ZEND_ARG_INFO(0, fd)
+	ZEND_ARG_TYPE_INFO(0, pos, IS_LONG, 0)
+	ZEND_ARG_TYPE_INFO_WITH_DEFAULT_VALUE(0, whence, IS_LONG, 0, "SEEK_SET")
+ZEND_END_ARG_INFO()
+
+#if !defined(PHP_WIN32)
+ZEND_BEGIN_ARG_INFO_EX(arginfo_dio_fcntl, 0, 0, 2)
+	ZEND_ARG_INFO(0, fd)
+	ZEND_ARG_TYPE_INFO(0, cmd, IS_LONG, 0)
+	ZEND_ARG_INFO_WITH_DEFAULT_VALUE(0, arg, "NULL")
+ZEND_END_ARG_INFO()
+#endif
+
+ZEND_BEGIN_ARG_WITH_RETURN_TYPE_MASK_EX(arginfo_dio_read, 0, 1, MAY_BE_LONG|MAY_BE_NULL|MAY_BE_FALSE)
+	ZEND_ARG_INFO(0, fd)
+	ZEND_ARG_TYPE_INFO_WITH_DEFAULT_VALUE(0, n, IS_LONG, 0, "1024")
+ZEND_END_ARG_INFO()
+
+ZEND_BEGIN_ARG_WITH_RETURN_TYPE_MASK_EX(arginfo_dio_write, 0, 2, MAY_BE_LONG|MAY_BE_FALSE)
+	ZEND_ARG_INFO(0, fd)
+	ZEND_ARG_TYPE_INFO(0, data, IS_STRING, 0)
+	ZEND_ARG_TYPE_INFO_WITH_DEFAULT_VALUE(0, len, IS_LONG, 0, "0")
+ZEND_END_ARG_INFO()
+
+ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX(arginfo_dio_close, 0, 1, IS_FALSE, 1)
+	ZEND_ARG_INFO(0, fd)
+ZEND_END_ARG_INFO()
+
+#if !defined(PHP_WIN32)
+ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX(arginfo_dio_tcsetattr, 0, 2, _IS_BOOL, 0)
+	ZEND_ARG_INFO(0, fd)
+	ZEND_ARG_TYPE_INFO(0, args, IS_ARRAY, 0)
+ZEND_END_ARG_INFO()
+#endif
+
+ZEND_BEGIN_ARG_INFO_EX(arginfo_dio_raw, 0, 0, 2)
+	ZEND_ARG_TYPE_INFO(0, filename, IS_STRING, 0)
+	ZEND_ARG_TYPE_INFO(0, mode, IS_STRING, 0)
+	ZEND_ARG_TYPE_INFO_WITH_DEFAULT_VALUE(0, options, IS_ARRAY, 1, "NULL")
+ZEND_END_ARG_INFO()
+
+#define arginfo_dio_serial arginfo_dio_raw
+
+
+ZEND_FUNCTION(dio_open);
+#if !defined(PHP_WIN32)
+ZEND_FUNCTION(dio_fdopen);
+#endif
+#if !defined(PHP_WIN32)
+ZEND_FUNCTION(dio_dup);
+#endif
+#if !defined(PHP_WIN32)
+ZEND_FUNCTION(dio_truncate);
+#endif
+ZEND_FUNCTION(dio_stat);
+ZEND_FUNCTION(dio_seek);
+#if !defined(PHP_WIN32)
+ZEND_FUNCTION(dio_fcntl);
+#endif
+ZEND_FUNCTION(dio_read);
+ZEND_FUNCTION(dio_write);
+ZEND_FUNCTION(dio_close);
+#if !defined(PHP_WIN32)
+ZEND_FUNCTION(dio_tcsetattr);
+#endif
+ZEND_FUNCTION(dio_raw);
+ZEND_FUNCTION(dio_serial);
+
+
+static const zend_function_entry ext_functions[] = {
+	ZEND_FE(dio_open, arginfo_dio_open)
+#if !defined(PHP_WIN32)
+	ZEND_FE(dio_fdopen, arginfo_dio_fdopen)
+#endif
+#if !defined(PHP_WIN32)
+	ZEND_FE(dio_dup, arginfo_dio_dup)
+#endif
+#if !defined(PHP_WIN32)
+	ZEND_FE(dio_truncate, arginfo_dio_truncate)
+#endif
+	ZEND_FE(dio_stat, arginfo_dio_stat)
+	ZEND_FE(dio_seek, arginfo_dio_seek)
+#if !defined(PHP_WIN32)
+	ZEND_FE(dio_fcntl, arginfo_dio_fcntl)
+#endif
+	ZEND_FE(dio_read, arginfo_dio_read)
+	ZEND_FE(dio_write, arginfo_dio_write)
+	ZEND_FE(dio_close, arginfo_dio_close)
+#if !defined(PHP_WIN32)
+	ZEND_FE(dio_tcsetattr, arginfo_dio_tcsetattr)
+#endif
+	ZEND_FE(dio_raw, arginfo_dio_raw)
+	ZEND_FE(dio_serial, arginfo_dio_serial)
+	ZEND_FE_END
+};
diff --git a/src/dio_legacy_arginfo.h b/src/dio_legacy_arginfo.h
new file mode 100644
index 0000000..5e6f4cc
--- /dev/null
+++ b/src/dio_legacy_arginfo.h
@@ -0,0 +1,124 @@
+/* This is a generated file, edit the .stub.php file instead.
+ * Stub hash: 74f93c791a08145405f1f08b0d8ee26876e92798 */
+
+ZEND_BEGIN_ARG_INFO_EX(arginfo_dio_open, 0, 0, 2)
+	ZEND_ARG_INFO(0, filename)
+	ZEND_ARG_INFO(0, flags)
+	ZEND_ARG_INFO(0, mode)
+ZEND_END_ARG_INFO()
+
+#if !defined(PHP_WIN32)
+ZEND_BEGIN_ARG_INFO_EX(arginfo_dio_fdopen, 0, 0, 1)
+	ZEND_ARG_INFO(0, fd)
+ZEND_END_ARG_INFO()
+#endif
+
+#if !defined(PHP_WIN32)
+#define arginfo_dio_dup arginfo_dio_fdopen
+#endif
+
+#if !defined(PHP_WIN32)
+ZEND_BEGIN_ARG_INFO_EX(arginfo_dio_truncate, 0, 0, 2)
+	ZEND_ARG_INFO(0, fd)
+	ZEND_ARG_INFO(0, offset)
+ZEND_END_ARG_INFO()
+#endif
+
+ZEND_BEGIN_ARG_INFO_EX(arginfo_dio_stat, 0, 0, 1)
+	ZEND_ARG_INFO(0, fd)
+ZEND_END_ARG_INFO()
+
+ZEND_BEGIN_ARG_INFO_EX(arginfo_dio_seek, 0, 0, 2)
+	ZEND_ARG_INFO(0, fd)
+	ZEND_ARG_INFO(0, pos)
+	ZEND_ARG_INFO(0, whence)
+ZEND_END_ARG_INFO()
+
+#if !defined(PHP_WIN32)
+ZEND_BEGIN_ARG_INFO_EX(arginfo_dio_fcntl, 0, 0, 2)
+	ZEND_ARG_INFO(0, fd)
+	ZEND_ARG_INFO(0, cmd)
+	ZEND_ARG_INFO(0, arg)
+ZEND_END_ARG_INFO()
+#endif
+
+ZEND_BEGIN_ARG_INFO_EX(arginfo_dio_read, 0, 0, 1)
+	ZEND_ARG_INFO(0, fd)
+	ZEND_ARG_INFO(0, n)
+ZEND_END_ARG_INFO()
+
+ZEND_BEGIN_ARG_INFO_EX(arginfo_dio_write, 0, 0, 2)
+	ZEND_ARG_INFO(0, fd)
+	ZEND_ARG_INFO(0, data)
+	ZEND_ARG_INFO(0, len)
+ZEND_END_ARG_INFO()
+
+#define arginfo_dio_close arginfo_dio_stat
+
+#if !defined(PHP_WIN32)
+ZEND_BEGIN_ARG_INFO_EX(arginfo_dio_tcsetattr, 0, 0, 2)
+	ZEND_ARG_INFO(0, fd)
+	ZEND_ARG_INFO(0, args)
+ZEND_END_ARG_INFO()
+#endif
+
+ZEND_BEGIN_ARG_INFO_EX(arginfo_dio_raw, 0, 0, 2)
+	ZEND_ARG_INFO(0, filename)
+	ZEND_ARG_INFO(0, mode)
+	ZEND_ARG_INFO(0, options)
+ZEND_END_ARG_INFO()
+
+#define arginfo_dio_serial arginfo_dio_raw
+
+
+ZEND_FUNCTION(dio_open);
+#if !defined(PHP_WIN32)
+ZEND_FUNCTION(dio_fdopen);
+#endif
+#if !defined(PHP_WIN32)
+ZEND_FUNCTION(dio_dup);
+#endif
+#if !defined(PHP_WIN32)
+ZEND_FUNCTION(dio_truncate);
+#endif
+ZEND_FUNCTION(dio_stat);
+ZEND_FUNCTION(dio_seek);
+#if !defined(PHP_WIN32)
+ZEND_FUNCTION(dio_fcntl);
+#endif
+ZEND_FUNCTION(dio_read);
+ZEND_FUNCTION(dio_write);
+ZEND_FUNCTION(dio_close);
+#if !defined(PHP_WIN32)
+ZEND_FUNCTION(dio_tcsetattr);
+#endif
+ZEND_FUNCTION(dio_raw);
+ZEND_FUNCTION(dio_serial);
+
+
+static const zend_function_entry ext_functions[] = {
+	ZEND_FE(dio_open, arginfo_dio_open)
+#if !defined(PHP_WIN32)
+	ZEND_FE(dio_fdopen, arginfo_dio_fdopen)
+#endif
+#if !defined(PHP_WIN32)
+	ZEND_FE(dio_dup, arginfo_dio_dup)
+#endif
+#if !defined(PHP_WIN32)
+	ZEND_FE(dio_truncate, arginfo_dio_truncate)
+#endif
+	ZEND_FE(dio_stat, arginfo_dio_stat)
+	ZEND_FE(dio_seek, arginfo_dio_seek)
+#if !defined(PHP_WIN32)
+	ZEND_FE(dio_fcntl, arginfo_dio_fcntl)
+#endif
+	ZEND_FE(dio_read, arginfo_dio_read)
+	ZEND_FE(dio_write, arginfo_dio_write)
+	ZEND_FE(dio_close, arginfo_dio_close)
+#if !defined(PHP_WIN32)
+	ZEND_FE(dio_tcsetattr, arginfo_dio_tcsetattr)
+#endif
+	ZEND_FE(dio_raw, arginfo_dio_raw)
+	ZEND_FE(dio_serial, arginfo_dio_serial)
+	ZEND_FE_END
+};
diff --git a/src/php_dio.h b/src/php_dio.h
index 1dda8ba..0b94cb9 100644
--- a/src/php_dio.h
+++ b/src/php_dio.h
@@ -31,17 +31,6 @@ PHP_RINIT_FUNCTION(dio);
 PHP_RSHUTDOWN_FUNCTION(dio);
 PHP_MINFO_FUNCTION(dio);
 
-/* Legacy functions. */
-PHP_FUNCTION(dio_open);
-PHP_FUNCTION(dio_truncate);
-PHP_FUNCTION(dio_stat);
-PHP_FUNCTION(dio_seek);
-PHP_FUNCTION(dio_read);
-PHP_FUNCTION(dio_write);
-PHP_FUNCTION(dio_fcntl);
-PHP_FUNCTION(dio_close);
-PHP_FUNCTION(dio_tcsetattr);
-
 typedef struct {
 	int fd;
 } php_fd_t;
diff --git a/src/php_dio_stream_wrappers.h b/src/php_dio_stream_wrappers.h
index 1226c72..746dd23 100644
--- a/src/php_dio_stream_wrappers.h
+++ b/src/php_dio_stream_wrappers.h
@@ -31,12 +31,8 @@
 
 extern php_stream_wrapper php_dio_raw_stream_wrapper;
 
-PHP_FUNCTION(dio_raw);
-
 extern php_stream_wrapper php_dio_serial_stream_wrapper;
 
-PHP_FUNCTION(dio_serial);
-
 #endif /* PHP_DIO_STREAM_WRAPPERS_H_ */
 
 /*