Hello Nikola, On 01/09/2018 02:54 PM, Nikola Forró wrote: > If an error occurs after at least one message has been received, > recvmmsg() call succeeds, and returns the number of messages received. > The error code is expected to be returned on a subsequent call. > In the current implementation, however, the error code can be overwritten > in the meantime by an unrelated network event on a socket, for example > an incoming ICMP packet. > > If an error occurs after at least one message has been sent, > sendmmsg() call succeeds, and returns the number of messages sent. > The error code is lost. The caller can retry the transmission, > starting at first failed message, but there is no guarantee that, > if an error is returned, it will be the same as the one that was lost > on the previous call. Thanks. Patch applied. (And thanks for your persistence.) Cheers, Michael > Reference: > https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git/tree/net/socket.c > > Signed-off-by: Nikola Forró <nforro@xxxxxxxxxx> > --- > man2/recvmmsg.2 | 10 ++++++++++ > man2/sendmmsg.2 | 8 ++++++++ > 2 files changed, 18 insertions(+) > > diff --git a/man2/recvmmsg.2 b/man2/recvmmsg.2 > index e7dfe848a..7a1be5787 100644 > --- a/man2/recvmmsg.2 > +++ b/man2/recvmmsg.2 > @@ -160,6 +160,8 @@ In addition, the following error can occur: > .B EINVAL > .I timeout > is invalid. > +.PP > +See also BUGS. > .SH VERSIONS > The > .BR recvmmsg () > @@ -179,6 +181,14 @@ so that if up to > .I vlen\-1 > datagrams are received before the timeout expires, > but then no further datagrams are received, the call will block forever. > +.PP > +If an error occurs after at least one message has been received, > +the call succeeds, and returns the number of messages received. > +The error code is expected to be returned on a subsequent call to > +.BR recvmmsq (). > +In the current implementation, however, the error code can be overwritten > +in the meantime by an unrelated network event on a socket, > +for example an incoming ICMP packet. > .SH EXAMPLE > .PP > The following program uses > diff --git a/man2/sendmmsg.2 b/man2/sendmmsg.2 > index a4895c1ac..ab08162bd 100644 > --- a/man2/sendmmsg.2 > +++ b/man2/sendmmsg.2 > @@ -134,6 +134,7 @@ is set to indicate the error. > Errors are as for > .BR sendmsg (2). > An error is returned only if no datagrams could be sent. > +See also BUGS. > .\" commit 728ffb86f10873aaf4abd26dde691ee40ae731fe > .\" ... only return an error if no datagrams could be sent. > .\" If less than the requested number of messages were sent, the application > @@ -165,6 +166,13 @@ is capped to > .\" For error handling an application using sendmmsg needs to retry at > .\" the first unsent message, so capping is simpler and requires less > .\" application logic than returning EINVAL. > +.SH BUGS > +If an error occurs after at least one message has been sent, > +the call succeeds, and returns the number of messages sent. > +The error code is lost. The caller can retry the transmission, > +starting at first failed message, but there is no guarantee that, > +if an error is returned, it will be the same as the one that was lost > +on the previous call. > .SH EXAMPLE > The example below uses > .BR sendmmsg () > -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/ -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
