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From s...@apache.org
Subject svn commit: r165212 - in /perl/modperl/docs/trunk/src/docs/2.0/api/APR: Error.pod Socket.pod
Date Thu, 28 Apr 2005 22:16:20 GMT
Author: stas
Date: Thu Apr 28 15:16:18 2005
New Revision: 165212

URL: http://svn.apache.org/viewcvs?rev=165212&view=rev
Log:
sock->recv may trigger both: is_EAGAIN and TIMEUP error:
nonblocking IO => is_EAGAIN
timeout(0)     => is_EAGAIN
timeout(1)     => TIMEUP 
so update the docs to include both

Modified:
    perl/modperl/docs/trunk/src/docs/2.0/api/APR/Error.pod
    perl/modperl/docs/trunk/src/docs/2.0/api/APR/Socket.pod

Modified: perl/modperl/docs/trunk/src/docs/2.0/api/APR/Error.pod
URL: http://svn.apache.org/viewcvs/perl/modperl/docs/trunk/src/docs/2.0/api/APR/Error.pod?rev=165212&r1=165211&r2=165212&view=diff
==============================================================================
--- perl/modperl/docs/trunk/src/docs/2.0/api/APR/Error.pod (original)
+++ perl/modperl/docs/trunk/src/docs/2.0/api/APR/Error.pod Thu Apr 28 15:16:18 2005
@@ -88,12 +88,16 @@
 
 There are two ways to figure out whether an error fits your case. In
 most cases you just compare C<$@> with an the error constant. For
-example:
+example if a socket has a timeout set and the data wasn't read within
+the timeout limit a
+C<L<APR::Const::TIMEUP|docs::2.0::api::APR::Const/C_APR__Const__TIMEUP_>>)
 
   use APR::Const -compile => qw(TIMEUP);
-  # some code throwing an exception
+  $sock->timeout_set(1_000_000); # 1 sec
+  my $buff;
+  eval { $socket->recv($buff, BUFF_LEN) };
   if ($@ && ref $@ && $@ == APR::Const::TIMEUP) {
-      # do something
+
   }
 
 However there are situations, where on different Operating Systems a
@@ -102,7 +106,9 @@
 C<L<APR::Status|docs::2.0::api::APR::Status>> class. One such
 condition is socket C<recv()> timeout, which on Unix throws the
 C<EAGAIN> error, but on other system it throws a different error. In
-this case L<APR::Status::is_EAGAIN> should be used.
+this case
+C<L<APR::Status::is_EAGAIN|docs::2.0::api::APR::Status/C_is_EAGAIN_>>
+should be used.
 
 Let's look at a complete example. Here is a code that performs L<a
 socket read|docs::2.0::api::APR::Socket/C_recv_>:

Modified: perl/modperl/docs/trunk/src/docs/2.0/api/APR/Socket.pod
URL: http://svn.apache.org/viewcvs/perl/modperl/docs/trunk/src/docs/2.0/api/APR/Socket.pod?rev=165212&r1=165211&r2=165212&view=diff
==============================================================================
--- perl/modperl/docs/trunk/src/docs/2.0/api/APR/Socket.pod (original)
+++ perl/modperl/docs/trunk/src/docs/2.0/api/APR/Socket.pod Thu Apr 28 15:16:18 2005
@@ -263,15 +263,43 @@
 
 If you get the C<'(11) Resource temporarily unavailable'> error
 (exception
-C<L<APR::Const::EAGAIN|docs::2.0::api::APR::Const/C_APR__EAGAIN_>>), then you
-didn't ensure that the socket is in L<a blocking IO mode|/C_opt_set_>
-before using it.
+C<L<APR::Const::EAGAIN|docs::2.0::api::APR::Const/C_APR__EAGAIN_>>)
+(or another equivalent, which might be different on non-POSIX
+systems), then you didn't ensure that the socket is in L<a blocking IO
+mode|/C_opt_set_> before using it. Note that you should use 
+C<L<APR::Status::is_EAGAIN|docs::2.0::api::APR::Status/C_is_EAGAIN_>>
+to perform this check (since different error codes may be returned for
+the same event on different OSes). For example if the socket is set to
+the non-blocking mode and there is no data right away, you may get
+this exception thrown. So here is how to check for it and retry a few
+times after short delays:
+
+  use APR::Status ();
+  $sock->opt_set(APR::Const::SO_NONBLOCK, 1);
+  # ....
+  my $tries = 0;
+  RETRY: my $rlen = eval { $socket->recv(my $buffer, SIZE) };
+  if ($@)
+      die $@ unless ref $@ && APR::Status::is_EAGAIN($@);
+      if ($tries++ < 3) {
+          # sleep 250msec
+          select undef, undef, undef, 0.25;
+          goto RETRY;
+      }
+      else {
+          # do something else
+      }
+  }
+  warn "read $rlen bytes\n"
+
 
 If timeout was set via C<timeout_set|/C_timeout_set_>, you may need to
-catch the C<L<APR::Const::TIMEUP|docs::2.0::api::APR::Const/C_APR__TIMEUP_>>
+catch the
+C<L<APR::Const::TIMEUP|docs::2.0::api::APR::Const/C_APR__TIMEUP_>>
 exception. For example:
 
   use APR::Const -compile => qw(TIMEUP);
+  $sock->timeout_set(1_000_000); # 1 sec
   my $buffer;
   eval { $sock->recv($buffer, $wanted) };
   if ($@ && $@ == APR::Const::TIMEUP) {



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