Index: src/OFDataArray.m
==================================================================
--- src/OFDataArray.m
+++ src/OFDataArray.m
@@ -18,12 +18,15 @@
 
 #import "OFDataArray.h"
 #import "OFExceptions.h"
 #import "OFMacros.h"
 
-static size_t lastpagebyte = 0;
-extern int getpagesize(void);
+#ifdef _WIN32
+#include <windows.h>
+#endif
+
+static int lastpagebyte = 0;
 
 @implementation OFDataArray
 + dataArrayWithItemSize: (size_t)is
 {
 	return [[[self alloc] initWithItemSize: is] autorelease];
@@ -185,12 +188,21 @@
 @implementation OFBigDataArray
 - initWithItemSize: (size_t)is
 {
 	self = [super initWithItemSize: is];
 
-	if (lastpagebyte == 0)
-		lastpagebyte = getpagesize() - 1;
+	if (lastpagebyte == 0) {
+#ifndef _WIN32
+		if ((lastpagebyte = sysconf(_SC_PAGESIZE)) == -1)
+			lastpagebyte = 4096;
+		lastpagebyte--;
+#else
+		SYSTEM_INFO si;
+		GetSystemInfo(&si);
+		lastpagebyte = si.dwPageSize - 1;
+#endif
+	}
 
 	return self;
 }
 
 - addItem: (void*)item

Index: src/OFStream.m
==================================================================
--- src/OFStream.m
+++ src/OFStream.m
@@ -16,18 +16,34 @@
 
 #import "OFStream.h"
 #import "OFExceptions.h"
 #import "OFMacros.h"
 
-extern int getpagesize(void);
+#ifdef _WIN32
+#include <windows.h>
+#endif
+
+static int pagesize = 0;
 
 @implementation OFStream
 - init
 {
 	self = [super init];
 
 	cache = NULL;
+
+#ifndef _WIN32
+	if (pagesize == 0)
+		if ((pagesize = sysconf(_SC_PAGESIZE)) == -1)
+			pagesize = 4096;
+#else
+	if (pagesize == 0) {
+		SYSTEM_INFO si;
+		GetSystemInfo(&si);
+		pagesize = si.dwPageSize - 1;
+	}
+#endif
 
 	return self;
 }
 
 - (size_t)readNBytes: (size_t)size
@@ -75,15 +91,15 @@
 			}
 		}
 	}
 
 	/* Read until we get a newline or \0 */
-	tmp = [self allocWithSize: getpagesize()];
+	tmp = [self allocWithSize: pagesize];
 
 	for (;;) {
 		@try {
-			len = [self readNBytes: getpagesize() - 1
+			len = [self readNBytes: pagesize - 1
 				    intoBuffer: tmp];
 		} @catch (OFException *e) {
 			[self freeMem: tmp];
 			@throw e;
 		}