Index: configure.ac
==================================================================
--- configure.ac
+++ configure.ac
@@ -693,10 +693,14 @@
 AS_IF([test x"$enable_files" != x"no"], [
 	AC_DEFINE(OF_HAVE_FILES, 1, [Whether we have files])
 	AC_SUBST(USE_SRCS_FILES, '${SRCS_FILES}')
 	AC_SUBST(OFHASH, "ofhash")
 	AC_SUBST(OFZIP, "ofzip")
+
+	AC_CHECK_TYPE(off64_t, [
+		AC_DEFINE(OF_HAVE_OFF64_T, 1, [Whether we have off64_t])
+	])
 
 	AC_CHECK_FUNCS(readdir_r)
 ])
 
 AC_CHECK_FUNCS([sysconf gmtime_r localtime_r nanosleep lstat])

Index: src/OFFile.h
==================================================================
--- src/OFFile.h
+++ src/OFFile.h
@@ -27,14 +27,16 @@
 #import "OFSeekableStream.h"
 
 @class OFArray;
 @class OFDate;
 
-#ifndef _WIN32
-typedef struct stat of_stat_t;
+#if defined(_WIN32)
+typedef struct __stat64 of_stat_t;
+#elif defined(OF_HAVE_OFF64_T)
+typedef struct stat64 of_stat_t;
 #else
-typedef struct _stat of_stat_t;
+typedef struct stat of_stat_t;
 #endif
 
 /*!
  * @class OFFile OFFile.h ObjFW/OFFile.h
  *

Index: src/OFFile.m
==================================================================
--- src/OFFile.m
+++ src/OFFile.m
@@ -124,12 +124,15 @@
 #endif
 
 int
 of_stat(OFString *path, of_stat_t *buffer)
 {
-#ifdef _WIN32
-	return _wstat([path UTF16String], buffer);
+#if defined(_WIN32)
+	return _wstat64([path UTF16String], buffer);
+#elif defined(OF_HAVE_OFF64_T)
+	return stat64([path cStringWithEncoding:
+	    [OFSystemInfo native8BitEncoding]], buffer);
 #else
 	return stat([path cStringWithEncoding:
 	    [OFSystemInfo native8BitEncoding]], buffer);
 #endif
 }
@@ -136,17 +139,27 @@
 
 int
 of_lstat(OFString *path, of_stat_t *buffer)
 {
 #if defined(_WIN32)
-	return _wstat([path UTF16String], buffer);
+	return _wstat64([path UTF16String], buffer);
 #elif defined(HAVE_LSTAT)
+# ifdef OF_HAVE_OFF64_T
+	return lstat64([path cStringWithEncoding:
+	    [OFSystemInfo native8BitEncoding]], buffer);
+# else
 	return lstat([path cStringWithEncoding:
 	    [OFSystemInfo native8BitEncoding]], buffer);
+# endif
 #else
+# ifdef OF_HAVE_OFF64_T
+	return stat64([path cStringWithEncoding:
+	    [OFSystemInfo native8BitEncoding]], buffer);
+# else
 	return stat([path cStringWithEncoding:
 	    [OFSystemInfo native8BitEncoding]], buffer);
+# endif
 #endif
 }
 
 static int
 parseMode(const char *mode)
@@ -893,16 +906,19 @@
 		if ((flags = parseMode([mode UTF8String])) == -1)
 			@throw [OFInvalidArgumentException exception];
 
 		flags |= O_CLOEXEC;
 
-#ifndef _WIN32
-		if ((_fd = open([path cStringWithEncoding: [OFSystemInfo
+#if defined(_WIN32)
+		if ((_fd = _wopen([path UTF16String], flags,
+		    DEFAULT_MODE)) == -1)
+#elif defined(OF_HAVE_OFF64_T)
+		if ((_fd = open64([path cStringWithEncoding: [OFSystemInfo
 		    native8BitEncoding]], flags, DEFAULT_MODE)) == -1)
 #else
-		if ((_fd = _wopen([path UTF16String], flags,
-		    DEFAULT_MODE)) == -1)
+		if ((_fd = open([path cStringWithEncoding: [OFSystemInfo
+		    native8BitEncoding]], flags, DEFAULT_MODE)) == -1)
 #endif
 			@throw [OFOpenFileFailedException
 			    exceptionWithPath: path
 					 mode: mode];
 	} @catch (id e) {
@@ -975,11 +991,17 @@
 }
 
 - (of_offset_t)lowlevelSeekToOffset: (of_offset_t)offset
 			     whence: (int)whence
 {
+#if defined(_WIN32)
+	of_offset_t ret = _lseeki64(_fd, offset, whence);
+#elif defined(OF_HAVE_OFF64_T)
+	of_offset_t ret = lseek64(_fd, offset, whence);
+#else
 	of_offset_t ret = lseek(_fd, offset, whence);
+#endif
 
 	if (ret == -1)
 		@throw [OFSeekFailedException exceptionWithStream: self
 							   offset: offset
 							   whence: whence];

Index: src/OFSeekableStream.h
==================================================================
--- src/OFSeekableStream.h
+++ src/OFSeekableStream.h
@@ -23,12 +23,16 @@
 
 #include <sys/types.h>
 
 #import "OFStream.h"
 
-#ifdef __ANDROID__
+#if defined(_WIN32)
+typedef __int64 of_offset_t;
+#elif defined(__ANDROID__)
 typedef long long of_offset_t;
+#elif defined(OF_HAVE_OFF64_T)
+typedef off64_t of_offset_t;
 #else
 typedef off_t of_offset_t;
 #endif
 
 /*!