--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/flang/runtime/environment.cpp	Mon May 25 11:55:54 2020 +0900
@@ -0,0 +1,39 @@
+//===-- runtime/environment.cpp ---------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "environment.h"
+#include <cstdio>
+#include <cstdlib>
+#include <limits>
+
+namespace Fortran::runtime {
+ExecutionEnvironment executionEnvironment;
+
+void ExecutionEnvironment::Configure(
+    int ac, const char *av[], const char *env[]) {
+  argc = ac;
+  argv = av;
+  envp = env;
+  listDirectedOutputLineLengthLimit = 79; // PGI default
+  defaultOutputRoundingMode =
+      decimal::FortranRounding::RoundNearest; // RP(==RN)
+
+  if (auto *x{std::getenv("FORT_FMT_RECL")}) {
+    char *end;
+    auto n{std::strtol(x, &end, 10)};
+    if (n > 0 && n < std::numeric_limits<int>::max() && *end == '\0') {
+      listDirectedOutputLineLengthLimit = n;
+    } else {
+      std::fprintf(
+          stderr, "Fortran runtime: FORT_FMT_RECL=%s is invalid; ignored\n", x);
+    }
+  }
+
+  // TODO: Set RP/ROUND='PROCESSOR_DEFINED' from environment
+}
+} // namespace Fortran::runtime