Merge pull request #3895 from mattn/fix-mkstemp

fix mkstemp implementation for MSVC

mrbgems/mruby-io/test/mruby_io_test.c

@@ -19,8 +19,14 @@ typedef int mode_t;
 static int
 mkstemp(char *p)
 {
-  _mktemp(p);
-  return 0;
+  int fd;
+  char* fname = _mktemp(p);
+  if (fname == NULL)
+    return -1;
+  fd = open(fname, O_RDWR | O_CREAT | O_EXCL, _S_IREAD | _S_IWRITE);
+  if (fd >= 0)
+    return fd;
+  return -1;
 }
 #endif
 
@@ -75,6 +81,9 @@ mrb_io_test_io_setup(mrb_state *mrb, mrb_value self)
     mrb_raise(mrb, E_RUNTIME_ERROR, "can't create temporary file");
     return mrb_nil_value();
   }
+  close(fd0);
+  close(fd1);
+
 #if !defined(_WIN32) && !defined(_WIN64)
   fd2 = mkstemp(symlinkname);
   fd3 = mkstemp(socketname);