#include <tcl.h> int Tcl_SetRecursionLimit(interp, depth)
At any given time Tcl enforces a limit on the number of recursive calls that may be active for Tcl_Eval and related procedures such as Tcl_GlobalEval. Any call to Tcl_Eval that exceeds this depth is aborted with an error. By default the recursion limit is 1000.
Tcl_SetRecursionLimit may be used to change the maximum allowable nesting depth for an interpreter. The depth argument specifies a new limit for interp, and Tcl_SetRecursionLimit returns the old limit. To read out the old limit without modifying it, invoke Tcl_SetRecursionDepth with depth equal to 0.