Index: include/ruby/win32.h
===================================================================
--- include/ruby/win32.h	(リビジョン 50766)
+++ include/ruby/win32.h	(作業コピー)
@@ -124,6 +124,8 @@ typedef unsigned int uintptr_t;
 
 #define WNOHANG -1
 
+#define O_DELETE 0x80000000 /* for rb_w32_open(), rb_w32_wopen() */
+
 typedef int clockid_t;
 #define CLOCK_REALTIME  0
 #define CLOCK_MONOTONIC 1
Index: io.c
===================================================================
--- io.c	(リビジョン 50766)
+++ io.c	(作業コピー)
@@ -175,6 +175,9 @@ static VALUE argf;
 static ID id_write, id_read, id_getc, id_flush, id_readpartial, id_set_encoding;
 static VALUE sym_mode, sym_perm, sym_extenc, sym_intenc, sym_encoding, sym_open_args;
 static VALUE sym_textmode, sym_binmode, sym_autoclose;
+#ifdef O_DELETE
+static VALUE sym_share_delete;
+#endif
 static VALUE sym_SET, sym_CUR, sym_END;
 #ifdef SEEK_DATA
 static VALUE sym_DATA;
@@ -5383,6 +5386,10 @@ rb_io_extract_modeenc(VALUE *vmode_p, VALUE *vperm
 		/* perm no use, just ignore */
 	    }
 	}
+#ifdef O_DELETE
+	v = rb_hash_aref(opthash, sym_share_delete);
+	if (!NIL_P(v)) oflags |= O_DELETE;
+#endif
 	ecflags = (fmode & FMODE_READABLE) ?
 	    MODE_BTMODE(ECONV_DEFAULT_NEWLINE_DECORATOR,
 			0, ECONV_UNIVERSAL_NEWLINE_DECORATOR) : 0;
@@ -12430,6 +12437,9 @@ Init_IO(void)
     sym_textmode = ID2SYM(rb_intern("textmode"));
     sym_binmode = ID2SYM(rb_intern("binmode"));
     sym_autoclose = ID2SYM(rb_intern("autoclose"));
+#ifdef O_DELETE
+    sym_share_delete = ID2SYM(rb_intern("share_delete"));
+#endif
     sym_normal = ID2SYM(rb_intern("normal"));
     sym_sequential = ID2SYM(rb_intern("sequential"));
     sym_random = ID2SYM(rb_intern("random"));
Index: win32/win32.c
===================================================================
--- win32/win32.c	(リビジョン 50766)
+++ win32/win32.c	(作業コピー)
@@ -5775,6 +5775,7 @@ rb_w32_open(const char *file, int oflag, ...)
     va_end(arg);
 
     if ((oflag & O_TEXT) || !(oflag & O_BINARY)) {
+	oflag &= ~O_DELETE;
 	ret = _open(file, oflag, pmode);
 	if (ret == -1 && errno == EACCES) check_if_dir(file);
 	return ret;
@@ -5797,7 +5798,10 @@ rb_w32_wopen(const WCHAR *file, int oflag, ...)
     DWORD attr = FILE_ATTRIBUTE_NORMAL;
     SECURITY_ATTRIBUTES sec;
     HANDLE h;
+    int delete;
 
+    delete = oflag & O_DELETE;
+    oflag &= ~O_DELETE;
     if ((oflag & O_TEXT) || !(oflag & O_BINARY)) {
 	va_list arg;
 	int pmode;
@@ -5919,8 +5923,7 @@ rb_w32_wopen(const WCHAR *file, int oflag, ...)
 	_set_osfhnd(fd, (intptr_t)INVALID_HANDLE_VALUE);
 	_set_osflags(fd, 0);
 
-	h = CreateFileW(file, access, FILE_SHARE_READ | FILE_SHARE_WRITE, &sec,
-			create, attr, NULL);
+	h = CreateFileW(file, access, FILE_SHARE_READ | FILE_SHARE_WRITE | (delete ? FILE_SHARE_DELETE : 0), &sec, create, attr, NULL);
 	if (h == INVALID_HANDLE_VALUE) {
 	    DWORD e = GetLastError();
 	    if (e != ERROR_ACCESS_DENIED || !check_if_wdir(file))