predef - variable protection
Utility function used for defining "oldest" variables as "protected". Protected variables cannot be killed. They are not saved by the 'save' command. The "oldest" are those appearing last in the who('get') .
predef() gets the number of protected variables
predef('a[ll]') sets all the variables protected, it also return the old and new value of protected variables number.
predef('c[lear]') unprotect all but the last 7 variables, it also return the old and new value of protected variables number.
predef(n) sets the max(n,7) last defined variables as protected, it also return the old and new value of protected variables number.
A number of protected variables are set in the start-up file SCIDIR/scilab.star . User may in particular set its own predefined variables in user's startup file home/.scilab