diff --git a/mmap/mmap_private.c b/mmap/mmap_private.c
index 4c7ad17..77a205d 100644
--- a/mmap/mmap_private.c
+++ b/mmap/mmap_private.c
@@ -12,7 +12,7 @@ char* mmap_private(const char* filename,unsigned long* filesize) {
 #ifdef __MINGW32__
   HANDLE fd,m;
   char* map;
-  fd=CreateFile(filename,GENERIC_READ,FILE_SHARE_READ,0,OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL,0);
+  fd=CreateFile(filename,GENERIC_WRITE|GENERIC_READ,FILE_SHARE_WRITE,0,OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL,0);
   if (fd==INVALID_HANDLE_VALUE)
     return 0;
   m=CreateFileMapping(fd,0,PAGE_WRITECOPY,0,0,NULL);
@@ -27,7 +27,7 @@ char* mmap_private(const char* filename,unsigned long* filesize) {
   char *map;
   if (fd>=0) {
     *filesize=lseek(fd,0,SEEK_END);
-    map=mmap(0,*filesize,PROT_WRITE,MAP_PRIVATE,fd,0);
+    map=mmap(0,*filesize,PROT_READ|PROT_WRITE,MAP_PRIVATE,fd,0);
     if (map==(char*)-1)
       map=0;
     close(fd);
diff --git a/mmap/mmap_shared.c b/mmap/mmap_shared.c
index 184ebff..086a7c8 100644
--- a/mmap/mmap_shared.c
+++ b/mmap/mmap_shared.c
@@ -12,7 +12,7 @@ extern char* mmap_shared(const char* filename,unsigned long* filesize) {
 #ifdef __MINGW32__
   HANDLE fd,m;
   char* map;
-  fd=CreateFile(filename,GENERIC_WRITE,FILE_SHARE_WRITE,0,OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL,0);
+  fd=CreateFile(filename,GENERIC_READ|GENERIC_WRITE,FILE_SHARE_WRITE,0,OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL,0);
   if (fd==INVALID_HANDLE_VALUE)
     return 0;
   m=CreateFileMapping(fd,0,PAGE_READWRITE,0,0,NULL);
@@ -27,7 +27,7 @@ extern char* mmap_shared(const char* filename,unsigned long* filesize) {
   char *map;
   if (fd>=0) {
     *filesize=lseek(fd,0,SEEK_END);
-    map=mmap(0,*filesize,PROT_WRITE,MAP_SHARED,fd,0);
+    map=mmap(0,*filesize,PROT_READ|PROT_WRITE,MAP_SHARED,fd,0);
     if (map==(char*)-1)
       map=0;
     close(fd);