Commit 0c9c4be4 authored by Alexandre Duret-Lutz's avatar Alexandre Duret-Lutz
Browse files

bin: workaround flushing issues

* bin/common_cout.cc (check_cout): Force a flush of cout if more than
20ms has elapsed since the last explicit flush.
* bin/common_setup.cc (setup): Untie cin and cout if the input
is not a TTY, so that cout is flush less often.
* NEWS: Mention the change.
parent 0678d1a6
......@@ -13,6 +13,14 @@ New in spot 2.1.1.dev (not yet released)
- Fix spurious uninitialized read reported by valgrind when
is_Kleene_star() is compiled by clang++.
- Using "ltlfilt some-large-file --some-costly-filter" could take
to a lot of time before displaying the first results, because the
output of ltlfilt is buffered: the buffer had to fill up before
being flushed. The issue did not manifest when the input is
standard input, because of the C++ feature that reading std::cin
should flush std::cout; however it was well visible when reading
from files. Flushing is now done more regularly.
New in spot 2.1.1 (2016-09-20)
Command-line tools:
......
// -*- coding: utf-8 -*-
// Copyright (C) 2012 Laboratoire de Recherche et Développement de
// Copyright (C) 2012, 2016 Laboratoire de Recherche et Développement de
// l'Epita (LRDE).
//
// This file is part of Spot, a model checking library.
......@@ -20,18 +20,42 @@
#include "common_sys.hh"
#include "common_cout.hh"
#include <iostream>
#include <chrono>
#include "error.h"
namespace
{
static std::chrono::steady_clock::time_point last_flush;
static void do_check_cout()
{
// Make sure we abort if we can't write to std::cout anymore
// (like disk full or broken pipe with SIGPIPE ignored).
if (!std::cout)
error(2, 0, "error writing to standard output");
}
}
void check_cout()
{
// Make sure we abort if we can't write to std::cout anymore
// (like disk full or broken pipe with SIGPIPE ignored).
if (!std::cout)
error(2, 0, "error writing to standard output");
// If we haven't flushed explicitly for more than 20ms, do it now.
// Otherwise we would have to wait for the buffer to fill up, and
// this could take a long time.
auto now = std::chrono::steady_clock::now();
auto ms =
std::chrono::duration_cast<std::chrono::milliseconds>(now - last_flush);
if (ms.count() >= 20)
{
last_flush = now;
std::cout.flush();
}
do_check_cout();
}
void flush_cout()
{
last_flush = std::chrono::steady_clock::now();
std::cout.flush();
check_cout();
do_check_cout();
}
......@@ -22,6 +22,7 @@
#include "argp.h"
#include <cstdlib>
#include <unistd.h>
#include <iostream>
#include <signal.h>
#include <sys/wait.h>
......@@ -83,6 +84,11 @@ setup(char** argv)
argp_err_exit_status = 2;
std::ios_base::sync_with_stdio(false);
// Do not flush std::cout every time we read from std::cin, unless
// we are reading from a terminal. Note that we do flush regularly
// in check_cout().
if (!isatty(STDIN_FILENO))
std::cin.tie(nullptr);
setup_default_output_format();
setup_sig_handler();
......
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