server.Server.load_buffer

Self::set_buffer carries the data as a command argument, which the kernel caps: on Linux a single argument stops at MAX_ARG_STRLEN, 128 KiB, and a larger one fails with "argument list too long" before tmux sees it. tmux opens the file itself here, so size is the file system's problem rather than the command line's.

path is tmux's to resolve, and tmux reads it as the user running the server, which is not necessarily this process.

Errors

Returns an error when tmux cannot read the path.