<div dir="ltr">Since sd_journal_send uses <br><br><div><span style="color:rgb(36,41,46);font-family:SFMono-Regular,Consolas,"Liberation Mono",Menlo,Courier,monospace;white-space:pre-wrap">fd = </span><span class="gmail-m_7512101758649824062gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197);font-family:SFMono-Regular,Consolas,"Liberation Mono",Menlo,Courier,monospace;white-space:pre-wrap">journal_fd</span><span style="color:rgb(36,41,46);font-family:SFMono-Regular,Consolas,"Liberation Mono",Menlo,Courier,monospace;white-space:pre-wrap">();</span> </div><div>which has <br><br></div><div><span style="color:rgb(36,41,46);font-family:SFMono-Regular,Consolas,"Liberation Mono",Menlo,Courier,monospace;white-space:pre-wrap">fd = </span><span class="gmail-m_7512101758649824062gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197);font-family:SFMono-Regular,Consolas,"Liberation Mono",Menlo,Courier,monospace;white-space:pre-wrap">socket</span><span style="color:rgb(36,41,46);font-family:SFMono-Regular,Consolas,"Liberation Mono",Menlo,Courier,monospace;white-space:pre-wrap">(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, </span><span class="gmail-m_7512101758649824062gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197);font-family:SFMono-Regular,Consolas,"Liberation Mono",Menlo,Courier,monospace;white-space:pre-wrap">0</span><span style="color:rgb(36,41,46);font-family:SFMono-Regular,Consolas,"Liberation Mono",Menlo,Courier,monospace;white-space:pre-wrap">);</span></div><div>this socket is opened without a non-blocking call.<br><br>This might cause the unix socket daemon to block this .<br><br>The other approach could be passing a nonblocking flag to <br><br><span style="color:rgb(36,41,46);font-family:SFMono-Regular,Consolas,"Liberation Mono",Menlo,Courier,monospace;white-space:pre-wrap"> k = </span><span class="gmail-m_7512101758649824062gmail-pl-c1" style="box-sizing:border-box;color:rgb(0,92,197);font-family:SFMono-Regular,Consolas,"Liberation Mono",Menlo,Courier,monospace;white-space:pre-wrap">sendmsg</span><span style="color:rgb(36,41,46);font-family:SFMono-Regular,Consolas,"Liberation Mono",Menlo,Courier,monospace;white-space:pre-wrap">(fd, &mh, MSG_NOSIGNAL);</span> </div><div><br></div><div><b style="color:rgb(68,68,68);font-family:verdana,helvetica,arial,sans-serif">MSG_DONTWAIT</b><span style="color:rgb(68,68,68);font-family:verdana,helvetica,arial,sans-serif"> flag . <br></span><br></div><div>ARE ANY OF THESE APPROACHES TRIED OR is there a plan to support this complete non blocking sd_journal_print call ? </div><div><br></div><div>regards<br> </div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, Jul 18, 2019 at 2:52 AM Mantas Mikulėnas <<a href="mailto:grawity@gmail.com">grawity@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div dir="ltr">On Thu, Jul 18, 2019 at 12:44 PM Ulrich Windl <<a href="mailto:Ulrich.Windl@rz.uni-regensburg.de" target="_blank">Ulrich.Windl@rz.uni-regensburg.de</a>> wrote:<br></div><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">>>> Mantas Mikulenas <<a href="mailto:grawity@gmail.com" target="_blank">grawity@gmail.com</a>> schrieb am 18.07.2019 um 10:06 in<br>
Nachricht<br>
<<a href="mailto:CAPWNY8XS1jw9iU_a-tagNw-v0NqeMAcWDRpftPdeKW_NFanqtA@mail.gmail.com" target="_blank">CAPWNY8XS1jw9iU_a-tagNw-v0NqeMAcWDRpftPdeKW_NFanqtA@mail.gmail.com</a>>:<br>
> On Thu, Jul 18, 2019 at 10:32 AM Ulrich Windl <<br>
> <a href="mailto:Ulrich.Windl@rz.uni-regensburg.de" target="_blank">Ulrich.Windl@rz.uni-regensburg.de</a>> wrote:<br>
> <br>
>> >>> Vaibhav Dahiya <<a href="mailto:vdahiya@ncsu.edu" target="_blank">vdahiya@ncsu.edu</a>> schrieb am 18.07.2019 um 02:53 in<br>
>> Nachricht<br>
>> <<a href="mailto:5d2fc2f0.1c69fb81.214d0.1aca@mx.google.com" target="_blank">5d2fc2f0.1c69fb81.214d0.1aca@mx.google.com</a>>:<br>
>> > Hello,<br>
>> ><br>
>> > I am using sd_journal_send api() api call to log messages on syslog<br>
>> server.<br>
>> > I see that this uses<br>
>> > sendmsg(fd, &mh, MSG_NOSIGNAL) call.<br>
>><br>
>> Aren't syslog messages UDP anyway? When would an UDP send block?<br>
>><br>
> <br>
> No, program APIs use Unix sockets (/dev/log, /run/systemd/journal/socket).<br>
> You only get UDP when your local syslog daemon is configured to forward<br>
> elsewhere.<br>
> <br>
> That said, both are datagram sockets, I'm not sure whether sending to Unix<br>
> dgram sockets can block or not?<br>
<br>
??? Datagram _is_ UDP<br></blockquote><div><br></div><div>UDP is datagram, but datagram is not always UDP.</div><div><br></div><div>"UDP" specifically means the datagram transport protocol that runs over IPv4/IPv6, nothing else. Unix sockets (AF_UNIX) have a datagram mode but they do not use UDP (or IP). Netlink is datagram-based but it isn't UDP-based. &c.</div></div><div><br></div>-- <br><div dir="ltr" class="gmail-m_3434070879003177447m_7452679602634841818gmail_signature"><div dir="ltr">Mantas Mikulėnas</div></div></div>
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<a href="https://lists.freedesktop.org/mailman/listinfo/systemd-devel" rel="noreferrer" target="_blank">https://lists.freedesktop.org/mailman/listinfo/systemd-devel</a></blockquote></div><br clear="all"><div><br></div>-- <br><div dir="ltr" class="gmail_signature"><div dir="ltr">Best Regards,<br><span style="color:rgb(136,136,136)">Vaibhav Dahiya</span><br style="color:rgb(136,136,136)"><span style="color:rgb(136,136,136)">Master's. Candidate in CSC (Computer Science) </span><br style="color:rgb(136,136,136)"><span style="color:rgb(136,136,136)">North Carolina State University</span><br style="color:rgb(136,136,136)"><span style="color:rgb(136,136,136)">Ph: </span><a value="+19198888429" style="color:rgb(17,85,204)">(919) 888-8429</a></div></div>