--- EV/Makefile.PL	2009/08/09 13:30:41	1.43
+++ EV/Makefile.PL	2020/02/18 18:26:47	1.68
@@ -1,10 +1,15 @@
-use 5.008002;
-
 use strict qw(vars subs);
+use Canary::Stability EV => 1, 5.008002;
 use Config;
 use ExtUtils::MakeMaker;
 
-unless (-e "libev/ev_epoll.c") {
+sub have_inc($) {
+   scalar grep -r "$_/$_[0]", $Config{usrinc}, split / /, $Config{incpth}
+}
+
+my $DEFINE;
+
+unless (-e "libev/ev_iouring.c") {
    print <<EOF;
 
 ***
@@ -37,7 +42,7 @@
 
 
 POSIX optionally offers support for a monotonic clock source. EV
-can take advantage of this clock source to detect time jumps
+can take advantage of this clock source to detect time jumps more
 reliably. Unfortunately, some systems are bound to be broken, so you can
 disable this here: you can completely disable the detection and use of
 the monotonic clock by answering 'n' here. Support for this clock type
@@ -46,7 +51,9 @@
 
 EOF
 
-my $DEFINE .= " -DEV_USE_MONOTONIC=" . (0 + (prompt ("Enable optional support for CLOCK_MONOTONIC (y/n)?", "y") =~ /[yY]/));
+unless (prompt ("Enable optional support for CLOCK_MONOTONIC (y/n)?", "y") =~ /[yY]/) {
+   $DEFINE .= " -DEV_USE_MONOTONIC=0";
+}
 
 print <<EOF;
 
@@ -57,7 +64,7 @@
 realtime clock interface. In a good implementation, using it is faster
 than the normal method of using gettimeofday. Unfortunately, this option
 is also bound to be broken on some systems, and current EV versions do not
-actually call C<gettimeofday> very often, so ti defaults to no.
+actually call gettimeofday very often, so it defaults to no.
 
 EOF
 
@@ -68,7 +75,7 @@
 *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
 
 
-EV can use various backends with various portability issue. The select
+EV can use various backends with various portability issues. The select
 backend is the most portable and makes for a good fallback, but it can be
 limited to a low number of file descriptors and/or might not compile. If
 you have problems with compiling ev_select.c, you might try to play around
@@ -95,10 +102,10 @@
 
    if (prompt ("Force use of system fd_set for select backend (y/n)?", "n") =~ /[yY]/) {
       $DEFINE .= " -DEV_SELECT_USE_FD_SET";
-   } 
+   }
 } else {
    $DEFINE .= " -DEV_USE_SELECT=0";
-} 
+}
 
 print <<EOF;
 
@@ -108,11 +115,11 @@
 The second very portable backend is poll(2). It does not exist on windows
 and various versions of Mac OS X (and on the other versions it simply
 doesn't work), but works basically everywhere else. It is recommended to use
-the default here unless you run into compile problems in ev_poll.c.
+the default here unless you run into compilation problems in ev_poll.c.
 
 EOF
 
-$DEFINE .= " -DEV_USE_POLL=" . (0 + (prompt ("Enable poll backend (y/n)?", (-e "/usr/include/poll.h") ? "y" : "n") =~ /[yY]/));
+$DEFINE .= " -DEV_USE_POLL=" . (0 + (prompt ("Enable poll backend (y/n)?", (have_inc "poll.h") ? "y" : "n") =~ /[yY]/));
 
 print <<EOF;
 
@@ -129,7 +136,7 @@
 
 EOF
 
-my $can_epoll = -e "/usr/include/sys/epoll.h";
+my $can_epoll = have_inc "sys/epoll.h";
 $can_epoll = $ENV{EV_EPOLL} if exists $ENV{EV_EPOLL};
 $DEFINE .= " -DEV_USE_EPOLL=" . (0 + (prompt ("Enable epoll backend (y/n)?", $can_epoll ? "y" : "n") =~ /[yY]/));
 
@@ -138,26 +145,110 @@
 *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
 
 
-Similarly to the epoll backend above, EV can take advantage of kqueue on
-many BSD systems. Support for kqueue will be detected at runtime, with a
-safe fallback to other methods when it cannot be used.
-
-Note that kqueue is broken on most operating systems, so by default it
-won't be used on many platforms, but you can still create your own event
-loop with kqueue backend if you ask specifically for it.
+Linux 4.18 introduced another event polling interface, this time using
+the Linux AIO API. While this API is far superior to epoll and almost
+rivals kqueue, it also suffers from the same issues as kqueue typically
+does: only a subset of file types are supported (as of 4.19, I have seen
+eventfd, pipes, sockets files and some devices, but no ttys). It also
+is subject arbitrary system-wide limits imposed on it. Therefore, this
+backend is not used by default, even when it is compiled in, and you have
+to request it explicitly, e.g. with LIBEV_FLAGS=64. If unsure, accept the
+default.
+
+EOF
+
+my $can_linuxaio = have_inc "linux/aio_abi.h";
+$can_linuxaio = $ENV{EV_LINUXAIO} if exists $ENV{EV_LINUXAIO};
+$can_linuxaio = 0 + (prompt ("Enable linux aio backend (y/n)?", $can_linuxaio ? "y" : "n") =~ /[yY]/);
+$DEFINE .= " -DEV_USE_LINUXAIO=$can_linuxaio";
+
+if ($can_linuxaio) {
+print <<EOF;
+
+*** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
+
+
+The previously mentioned Linux AIO backend is experimental and will not
+be used unless requested explicitly. You can, howeer, choose to make ti a
+recommended basckend, which means it will be chosen if available even when
+not explicitly asked for, in preference to epoll on GNU/Linux. This option
+is likely temporary. When unsure, accept the default.
+
+EOF
+
+my $recommend_linuxaio = 0;
+$recommend_linuxaio = $ENV{EV_RECOMMEND_LINUXAIO} if exists $ENV{EV_RECOMMEND_LINUXAIO};
+$recommend_linuxaio = 0 + (prompt ("Treat linux aio as a recommended backend (y/n)?", $recommend_linuxaio ? "y" : "n") =~ /[yY]/);
+$DEFINE .= " -DEV_RECOMMEND_LINUXAIO=$recommend_linuxaio";
+}
+
+print <<EOF;
+
+*** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
+
+
+Linux 4.19 introduced another event polling interface, "io_uring". While
+this API is far superior to epoll and almost rivals linuxaio, it also
+suffers from the same issues as kqueue typically does: only a subset of
+file types are supported (as of 5.2). It is also very buggy still, and
+most importantly, very very slow for most workloads.  Therefore, this
+backend is not used by default, even when it is compiled in, and you have
+to request it explicitly, e.g. with LIBEV_FLAGS=128. If unsure, accept the
+default.
+
+EOF
+
+my $can_iouring = have_inc "linux/fs.h";
+$can_iouring = $ENV{EV_IOURING} if exists $ENV{EV_IOURING};
+$can_iouring = 0 + (prompt ("Enable linux io_uring backend (y/n)?", $can_iouring ? "y" : "n") =~ /[yY]/);
+$DEFINE .= " -DEV_USE_IOURING=$can_iouring";
+
+if ($can_iouring) {
+print <<EOF;
+
+*** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
+
+
+The previously mentioned Linux io_uring is experimental and will not be
+used unless requested explicitly. You can, howeer, choose to make ti a
+recommended basckend, which means it will be chosen if available even when
+not explicitly asked for, in preference to epoll on GNU/Linux. This option
+is likely temporary. When unsure, accept the default.
+
+EOF
+
+my $recommend_iouring = 0;
+$recommend_iouring = $ENV{EV_RECOMMEND_IOURING} if exists $ENV{EV_RECOMMEND_IOURING};
+$recommend_iouring = 0 + (prompt ("Treat io_uring as a recommended backend (y/n)?", $recommend_iouring ? "y" : "n") =~ /[yY]/);
+$DEFINE .= " -DEV_RECOMMEND_IOURING=$recommend_iouring";
+}
+
+print <<EOF;
+
+*** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
+
+
+EV can take advantage of kqueue on many BSD systems. Support for kqueue
+will be detected at runtime, with a safe fallback to other methods when it
+cannot be used.
+
+Note that kqueue is subtly broken on most operating systems, so by default
+it won't be used on many platforms, but you can still create your own
+event loop with kqueue backend if you ask specifically for it.
 
 Here is what we know:
 
-NetBSD:  partially working in at least 3.1. Yeah! :)
-FreeBSD: broken on at least 6.2-STABLE,
+NetBSD:  partially working in at least 3.1 and later. Yeah! :)
+FreeBSD: broken on at least 6.2-STABLE, spotty in later versions,
          sockets *likely* work, ptys definitely don't.
 OpenBSD: reports indicate that it likely doesn't work
          (similar problems as on FreeBSD).
-OS X:    completely, utterly broken on at least < 10.5.
+OS X:    completely, utterly broken on at least <= 10.6.
 
 EOF
 
-my $can_kqueue = -e "/usr/include/sys/event.h";
+# minix has all the header files, but no implementation. won-der-ful.
+my $can_kqueue = have_inc "sys/event.h" && $^O ne "minix";
 $can_kqueue = $ENV{EV_KQUEUE} if exists $ENV{EV_KQUEUE};
 $DEFINE .= " -DEV_USE_KQUEUE=" . (0 + (prompt ("Enable kqueue backend (y/n)?", $can_kqueue ? "y" : "n") =~ /[yY]/));
 
@@ -172,7 +263,7 @@
 
 EOF
 
-$DEFINE .= " -DEV_USE_PORT=" . (0 + (prompt ("Enable event port backend (y/n)?", (-e "/usr/include/sys/port.h") ? "y" : "n") =~ /[yY]/));
+$DEFINE .= " -DEV_USE_PORT=" . (0 + (prompt ("Enable event port backend (y/n)?", (have_inc "sys/port.h") ? "y" : "n") =~ /[yY]/));
 
 print <<EOF;
 
@@ -184,11 +275,16 @@
 can specify additional libraries to provide these calls (and any other
 required by EV) now, or accept the default.
 
+On GNU/Linux systems, EV uses the LSB 3.1 __register_atfork function
+to avoid the dependency on libpthread, and directly uses the clock_gettime
+syscall to avoid a dependency on librt.
+
 EOF
 
 my $solaris_libs = $^O =~ /solaris/i ? "-lsocket -lnsl" : "";
-my $librt = $^O =~ /linux/i ? "-lpthread" : "-lpthread -lrt";
-my $LIBS = prompt "Extra libraries for pthread_atfork and clock_gettime?", "$librt $solaris_libs";
+my $librt = $^O =~ /linux/i ? "" : "-lpthread -lrt";
+my $LIBS = exists $ENV{EV_LIBS} ? $ENV{EV_LIBS} : "$librt $solaris_libs";
+$LIBS = prompt "Extra libraries for pthread_atfork and clock_gettime?", $LIBS;
 
 
 print <<EOF;
@@ -203,7 +299,7 @@
 
 EOF
 
-my $can_inotify = -e "/usr/include/sys/inotify.h";
+my $can_inotify = have_inc "sys/inotify.h";
 $can_inotify = $ENV{EV_INOTIFY} if exists $ENV{EV_INOTIFY};
 $DEFINE .= " -DEV_USE_INOTIFY=" . (0 + (prompt ("Enable inotify support (y/n)?", $can_inotify ? "y" : "n") =~ /[yY]/));
 
@@ -220,7 +316,7 @@
 
 EOF
 
-my $can_eventfd = -e "/usr/include/sys/eventfd.h";
+my $can_eventfd = have_inc "sys/eventfd.h";
 $can_eventfd = $ENV{EV_EVENTFD} if exists $ENV{EV_EVENTFD};
 $DEFINE .= " -DEV_USE_EVENTFD=" . (0 + (prompt ("Enable linux eventfd support (y/n)?", $can_eventfd ? "y" : "n") =~ /[yY]/));
 
@@ -232,11 +328,11 @@
 Another sometimes useful bit of functionality is the Linux signalfd, which
 is useful for faster signal handling (don't care). Kernel support for
 this will be probed at runtime, but your libc must contain the necessary
-wrapper and include files. Glibc 2.9 and later should have this wrapper.
+wrapper. Glibc 2.7 and later should have this wrapper.
 
 EOF
 
-my $can_signalfd = -e "/usr/include/sys/signalfd.h";
+my $can_signalfd = have_inc "sys/signalfd.h";
 $can_signalfd = $ENV{EV_SIGNALFD} if exists $ENV{EV_SIGNALFD};
 $DEFINE .= " -DEV_USE_SIGNALFD=" . (0 + (prompt ("Enable linux signalfd support (y/n)?", $can_signalfd ? "y" : "n") =~ /[yY]/));
 
@@ -245,9 +341,67 @@
 *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
 
 
+Linux kernels can notify userspace about realtime clock timejumps
+using timerfd. Libev by default will try to take advantage of this if
+possible. You can completely disable the detection and use of timerfd for
+this purpose by answering 'n' here. Support for timerfd will otherwise be
+autodetected at both compile- and runtime.
+
+EOF
+
+unless (prompt ("Enable optional support for timerfd to detect timejumps (y/n)?", "y") =~ /[yY]/) {
+   $DEFINE .= " -DEV_USE_TIMERFD=0";
+}
+
+print <<EOF;
+
+*** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
+
+
+Libev contains numerous internal assert() invocations to check for
+consistency and user errors. These are normally enabled, but most
+perl builds disable this error reporting mechanism by default. You
+can re-enable these asserts here. Enabling them might help you catch
+programming bugs earlier, but might cause a small slowdown. Also, failures
+will be reported by aboritng your program, instead of throwing a perl
+exception.
+
+If unsure, enable this if you only use this perl installation for
+development, and leave it off for use in production environments.
+
+EOF
+
+my $enable_assertions = 0;
+$enable_assertions = 0 + (prompt ("Make sure assertions are enabled? (y/n)?", $enable_assertions ? "y" : "n") =~ /[yY]/);
+$DEFINE .= " -DEV_ENABLE_ASSERTIONS=1" if $enable_assertions;
+
+print <<EOF;
+
+*** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
+
+
+Very rarely, people want to tweak EV even more, e.g. to exclude
+or include certain watcher types or backends. This can be done by adding
+extra -D options here, or via the EV_EXTRA_DEFS environment variable.
+
+For example, if you run into compilation problems because of missing memory
+fences (or you just want extra performance), you can tell EV to not support
+smp and threads via -DEV_NO_THREADS.
+
+Most people would just press enter.
+
 EOF
 
-my @anyevent = eval { require AnyEvent; $AnyEvent::VERSION < 2.6 } ? (AnyEvent => 2.6) : ();
+$DEFINE .= " " . prompt "Any extra -D options?", "$ENV{EV_EXTRA_DEFS}";
+
+print <<EOF;
+
+*** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
+
+
+EOF
+
+my @anyevent = eval { require AnyEvent; $AnyEvent::VERSION < 5.29 } ? (AnyEvent => 5.29) : ();
 
 WriteMakefile(
     dist	=> {
@@ -257,7 +411,7 @@
 	           },
     depend => {
        "EV.c" => "EV/EVAPI.h "
-               . "libev/ev.c libev/ev.h libev/ev_epoll.c libev/ev_select.c libev/ev_kqueue.c libev/ev_poll.c "
+               . "libev/ev.c libev/ev.h libev/ev_epoll.c libev/ev_select.c libev/ev_kqueue.c libev/ev_poll.c libev/ev_linuxaio.c "
                . "libev/ev_vars.h libev/ev_wrap.h",
     },
     INC       => "-Ilibev",
@@ -268,13 +422,14 @@
        @anyevent,
        "common::sense" => 0,
     },
+    CONFIGURE_REQUIRES => { "ExtUtils::MakeMaker" => 6.52, "Canary::Stability" => 0 },
     VERSION_FROM => "EV.pm",
     PM           => {
-    		    'EV.pm'		=> '$(INST_LIBDIR)/EV.pm',
-    		    'EV/EVAPI.h'	=> '$(INST_LIBDIR)/EV/EVAPI.h',
-    		    'EV/MakeMaker.pm'	=> '$(INST_LIBDIR)/EV/MakeMaker.pm',
-    		    'libev/ev.h'	=> '$(INST_LIBDIR)/EV/ev.h',
-    		    'libev/ev.pod'	=> '$(INST_LIBDIR)/EV/libev.pod',
+		    'EV.pm'		=> '$(INST_LIB)/EV.pm',
+		    'EV/EVAPI.h'	=> '$(INST_LIB)/EV/EVAPI.h',
+		    'EV/MakeMaker.pm'	=> '$(INST_LIB)/EV/MakeMaker.pm',
+		    'libev/ev.h'	=> '$(INST_LIB)/EV/ev.h',
+		    'libev/ev.pod'	=> '$(INST_LIB)/EV/libev.pod',
                  },
     MAN3PODS => {
                     'EV.pm'           => '$(INST_MAN3DIR)/EV.$(MAN3EXT)',
@@ -283,4 +438,3 @@
                 },
 );
 
-