/usr/share/psychtoolbox-3/PsychBasic/GetPID.m is in psychtoolbox-3-common 3.0.11.20140816.dfsg1-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 | function pid=GetPID
% pid=GetPID
%
% Return the process ID of the MATLAB process. GetPID calls the POSIX
% function "getpid".
%
PsychAssertMex;
|