Core C++ 2021

Core C++ <local> 2021 :: Organizers Report



Core C++ <local> 2021 took place on Aug. 25-26 2021 in Tel-Aviv, Israel.
It was a full face-to-face conference and was a huge success.
This post is aimed mostly at community and conference organizers, sharing our experiences with a COVID-19 era in-person conference. Naturally, every conference is different and each country has its own vaccination rates, regulations and policies so use this summary as a reference not as a guaranteed guide to success.

Quick Recap

Core C++ 2019 took place in May 2019. It was the first ever C++ conference in Israel and was guided more by enthusiasm than hard data. It was a huge success, featuring multiple top international speakers and plotted a bright path to even bigger future conferences. The event was sold out with over 350 attendees.

After the previous year’s success, Core C++ 2020 was even more ambitious. It was moved to a new venue to allow over 500 participants, three tracks and flying in more international speakers including a keynote by Bjarne Stroustrup. Unfortunately, due to COVID-19 lockdowns and restrictions, the conference was cancelled. At cancellation time, all tickets that had already been purchased were refunded to their buyers.

Planning Core C++ <local> 2021

In late May 2021 after three countrywide COVID-19 lockdowns, a large majority of Israel’s population was already vaccinated and a new lockdown was looking less and less probable as more and more restrictions on public gatherings were lifted. The Core C++ program committee convened and we decided to try and figure out how to organize a conference later in the year.

We decided very early on against an online conference. We believe that the true value of a conference is in the “hallway tracks” and the informal meetings of the community. This is true both for the participants and of course for the sponsors too.

Our first and foremost guideline was Risk Reduction. This included financial risk reductions, health and safety issues and also scheduling and program risk reductions.

Travel to and from Israel and other countries is (still) restricted and under constantly changing isolation and COVID-19 testing requirements. Such uncertainty made it clear that even if we made the financial commitments of flying international speakers in, we would not be able to count on them being allowed to attend. So under the principle of risk reduction, the conference name was changed to Core C++ <local> 2021 and we decided to call for and accept only local Israeli speakers. In retrospect, this was essential for reducing both the cost and the risk for last minute program changes. That being said, for our grand plenary keynote, Bjarne Stroustrup graciously agreed to deliver his talk and Q&A live via Zoom.

Core C++ <local> 2021

The dates for the conference were set to the end of August for several reasons. First, the Academic College of Tel-Aviv-Yaffo, our gracious venue host, was student-free for summer break. This meant less people on campus, access to the largest auditoriums and classes as needed and lots of parking. Second, due to international travel restrictions it was significantly less likely that most people would be on end-of-August summer vacations abroad (as is the case in most years). Third, as these dates were chosen in early June, we wanted as much remaining time as possible to organize and to hopefully allow for more COVID-19 restrictions to be lifted, but still have the conference before the series of holidays which start at the Hebrew Calendar New Year in early Sept. 2021. Besides many folks being on holiday in Sept., it was quite probable that more restriction would be set in place (if not a full lockdown) to prevent contagion during these times of cross-country family gatherings.


From the outset, the conference was planned to adhere to the Ministry of Health (MoH) COVID-19 guidelines. These dictate the rules for open and closed public place gatherings and other related regulations. The GreenPass is Israel’s individual certificate for vaccinated and recovered people and allows entry to all GreePass required locations.

A Positive Meetup

On a Wednesday evening, three weeks before the conference, The Core C++ User Group had its first face-to-face meetup after 13 months of online meetings. Entry to the meetup required a GreenPass or a validated recent negative COVID-19 test result and masks were worn by all the participants during the meeting.
Unfortunately, a few days later we were notified that one of the attendees, despite being doubly vaccinated, was later identified as COVID-19 positive. We do not know whether the infection was before or after the meetup.

On the one hand, as-per the GreenPass regulations none of the vaccinated participants were required to go into isolation. However, this did emphasize for us the importance of strict compliance with regulations. We sent out a notification email to all participants to get tested just in case.

Proactive Planning

Despite the optimistic lookout when the conference planning began, in the 3-4 weeks leading to the conference dates, the COVID-19 delta variant began spreading rapidly in Israel. In response, more and more folks were receiving a 3rd vaccination booster-shot. These booster shots appear to reduce infection and sickness rates. Concurrently, the MoH began updating and changing the limitations on public gatherings in open and closed spaces. The limits dropped from 5000 people to 1000 then to 500.

Two weeks before the conference, we stopped selling more tickets so that even if the number of allowed public gatherings was limited to 100 (it wasn’t), we would still be able to accommodate less than 100 folks in each auditorium. Under these new regulations, entry to the college campus itself (outside the venue itself) was to require showing a GreenPass or a valid negative test.

At this time we began getting concerned inquiries from both participants and sponsors regarding the actions we are taking with the new COVID restrictions and regarding cancellations. Having learned our lesson in the Meetup, and to alleviate such concerns, we made the decision to be even stricter than the MoH guidelines. We will have an on-premises rapid antigen testing station outside the venue building. As part of the conference registration process, every attendee was required to show a negative test result upon which they got a green Tyvek wristband. The green bands conveyed a feeling of safety among the participants in the hall and expo areas when everyone has one. Anyone with a positive result would be regretfully sent home and fully refunded their ticket. A second testing station was set up outside the college premises to allow unvaccinated people to enter the college and the conference upon receiving a negative result. We tried to gather as much information about the accuracy of the rapid tests and the False-Positive rates. In the end we determined that even if we had to send home and refund a small number of individuals, it would still be worth it. The cost for the rapid testing was covered by the conference. We sent out an email to all the participants and sponsors clearly explaining all of this.


As part of our dynamic restriction reaction stance, we removed the dates on any printed material such as Tee-shirts, bags and placards. This was done in case the conference would have to be postponed from the published dates. Fortunately this did not happen and the conference took place as originally planned.

Conference Day

The conference was a great success. The rapid COVID-19 antigen testing station proved effective. People stood in line patiently and waited outside the building to get their results which came in within approx. 15-12 minutes. The testing station and waiting area was shaded and a table with cold water kept people hydrated and calm. Upon receiving the negative results, a participant would register, get their goodie bag and tee-shirt, get their green wristband and was free to enter the expo lobby. As it turned out, of the 227 people tested (some were expo and other staff) none came back positive for COVID-19.

In the expo lobby and certainly within the auditorium halls, the audience kept their face masks on and we did not have nor received any reports of any issues and problems. At the beginning of each day, the plenary audience was reminded that they must keep their face masks on at all times.

Lunch and refreshments were served at multiple buffet carts in a large side-room with standing tables and (biodegradable) disposable tableware. Lines for lunch were relatively short and folks kept calm with their face masks on.

Over twenty student volunteers helped at the registration desk and the lobby entrance to ensure everyone entring had the green wristband.

A few more issues perhaps worth mentioning:

  1. The rapid antigen testing station staff came in about one hour late which caused a delay in getting back the test results and thus the start of the day. We started about 30 min. later than planned but by shortening the coffee breaks managed to go back to the original schedule by lunch time. We got great feedback on the rapid test station, it was essential for making both the participants and the sponsors feel safer during the conference, and essentially payed for itself by preventing cancellations.
  2. The rapid antigen tests were valid for only 24 hours. Despite this we decided that the on-premises testing station would only be operated on the first day of the conference. We determined that the risk of a sudden infection on the second day was very low and so anyone who attended the first day and who had a valid GreenPass, would be allowed on the second day. We encouraged people to keep their wristbands on for the second day. Unvaccinated people had to get a new valid negative test result independently.
  3. The rapid test results were sent to the email address provided by the participants. As it turned out, not all participants had access to work emails on their phones, so a few individuals required manual result checking with the testing representative’s system. This was a minor issue.

All in all, the conference experience was very good. Attendance was approx. 220 people - mostly due to our cautious ticket number restrictions. There were approx. 50 more people on the waiting list. Initial and unsolicited feedback we have shows that even the most worrisome, health and safety conscious individuals felt safe and that sufficient precautions were taken. We received many commendations for the event and no complaints over risky or irresponsible actions.

Hopefully, Core C++ 2022 will take place in-person without a lot of the drama required for this year’s event and with many overseas speakers too!


To summarize, we identify several factors that we believe contributed to the success of the conference:

  1. Risk Mitigation
    We were more stringent than MoH guidelines.
    We believe this was a good decision with a positive effect on both participants and sponsors.
  2. Transparency
    We sent email notifications explaining how we are adapting to new guidelines, the safety measures we are taking and the logistical repercussions of these measures. Note that email phrasing is very important. We could not legally force people to take the rapid tests, we could only enforce the MoH “GreenPass” requirements. With careful phrasing and proper site and entry placements we encouraged it and “nudged” people to default to taking the rapid test. Ultimately, there were no issues with participants opposing the tests, but one should be prepared for such an event when it occurs and prepare accordingly.
  3. Visibility
    For increasing the participants’ peace of mind (as well as sponsors and organizers), we recommend to have facilities such as Wristbands to identify negatively tested participants, visible restricted access areas and testing station location signs to visibly indicate the hall and expo boundaries and explicitly requesting participants to keep their masks on. Spare masks were available at the registration table throughout the day.

It is possible to have a safe and successful face-to-face conference in 2021 (at least in Israel). At no time did we, the organizers, nor the participants (attendeeds or sponsors) feel that the the operation was irresponsible or negligant.


I am grateful to my co-organizers Michael Gopshtein, Inbal Levi, Eran Gilad and Amir Kirsh for their great efforts behind the scenes to make Core C++ such a grand success and Yardena Kamhaji from The Academic College of Tel-Aviv-Yaffo for orchestraing this grand production from bags and tees to booths and teas.

Thanks to Yehezkel Bernat for proofreading and corrections.

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