interp recursionlimit path ?newlimit?
Returns the maximum allowable nesting depth for the interpreter specified by path. If newlimit is specified, the interpreter recursion limit will be set so that nesting of more than newlimit calls to Tcl_Eval() and related procedures in that interpreter will return an error. The newlimit value is also returned. The newlimit value must be a positive integer between 1 and the maximum value of a non-long integer on the platform.
The command sets the maximum size of the Tcl call stack only. It cannot by itself prevent stack overflows on the C stack being used by the application. If your machine has a limit on the size of the C stack, you may get stack overflows before reaching the limit set by the command. If this happens, see if there is a mechanism in your system for increasing the maximum size of the C stack.