macOS: OSError: [Errno 24] Too many open files

[papr]

Pupil Core software uses a varying number of file handles, depending on

• the enabled plugins
• the number of ZRE clients (auto-discovery protocol used for pyndsi, Pupil Groups, and Time Sync)

macOS has a soft-limit regarding the maximum number of open file handles (required for inter-process communication and network sockets, too). This value can be unexpectedly low, e.g. 256. Pupil Capture crashes if it hits this limit.

One can see the current limit by running ulimit -n or launchctl limit maxfiles in the terminal.

This article proposes increasing the soft-limit using this command:

sudo launchctl limit maxfiles 10000 2147483647

Do not increase the second number.