I downloaded Nagios Core 4.2.0 source and compiled on Mac OS 10.11 aka El Capitan. Upon execution I get a segmentation fault.
bash-3.2$ ./nagios /Library/Server/Web/Data/Sites/Default/nagios/etc/nagios.cfg
Nagios Core 4.2.0
Copyright (c) 2009-present Nagios Core Development Team and Community Contributors
Copyright (c) 1999-2009 Ethan Galstad
Last Modified: 08-01-2016
License: GPL
Website: https://www.nagios.org
Nagios 4.2.0 starting... (PID=79592)
Local time is Sun Aug 07 18:59:29 PDT 2016
nerd: Channel hostchecks registered successfully
nerd: Channel servicechecks registered successfully
nerd: Channel opathchecks registered successfully
nerd: Fully initialized and ready to rock!
wproc: Successfully registered manager as @wproc with query handler
wproc: Registry request: name=Core Worker 79594;pid=79594
wproc: Registry request: name=Core Worker 79595;pid=79595
wproc: Registry request: name=Core Worker 79596;pid=79596
wproc: Registry request: name=Core Worker 79593;pid=79593
wproc: Registry request: name=Core Worker 79597;pid=79597
wproc: Registry request: name=Core Worker 79598;pid=79598
Segmentation fault: 11
bash-3.2$
Does anyone have any ideas on a way to get it to work on Mac OS 10.11 and/or how to formally open this as a bug?
Nagios Core on Mac OS 10.11 Segmentation Fault
Re: Nagios Core on Mac OS 10.11 Segmentation Fault
Segfaults in particular can be difficult to pin down. Internally, there isn't much testing done with OS X (since we don't have a system to test against).
https://github.com/NagiosEnterprises/nagioscore/issues
The github is the best place to report bugs and is probably the best way to get a resolution for this issue:Josh3955 wrote:how to formally open this as a bug?
https://github.com/NagiosEnterprises/nagioscore/issues
Former Nagios employee
https://www.mcapra.com/
https://www.mcapra.com/
Re: Nagios Core on Mac OS 10.11 Segmentation Fault
Thanks, I opened #151 on there. Crossing my fingers 
Re: Nagios Core on Mac OS 10.11 Segmentation Fault
Thanks! Going to close this up, since it is a developer concern and has been filed on GitHub.
Former Nagios employee