osx man page for tcl_allowexceptions

Tcl_AllowExceptions(3)					      Tcl Library Procedures					    Tcl_AllowExceptions(3)

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NAME
       Tcl_AllowExceptions - allow all exceptions in next script evaluation

SYNOPSIS
       #include <tcl.h>

       Tcl_AllowExceptions(interp)

ARGUMENTS
       Tcl_Interp *interp (in)		Interpreter in which script will be evaluated.
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DESCRIPTION
       If  a  script is evaluated at top-level (i.e. no other scripts are pending evaluation when the script is invoked), and if the script termi-
       nates with a completion code other than TCL_OK, TCL_ERROR or TCL_RETURN, then Tcl normally converts this into a TCL_ERROR  return  with	an
       appropriate  message.  The particular script evaluation procedures of Tcl that act in the manner are Tcl_EvalObjEx, Tcl_EvalObjv, Tcl_Eval,
       Tcl_EvalEx, Tcl_GlobalEval, Tcl_GlobalEvalObj, Tcl_VarEval and Tcl_VarEvalVA.

       However, if Tcl_AllowExceptions is invoked immediately before calling one of those a procedures, then arbitrary completion codes  are  per-
       mitted from the script, and they are returned without modification.  This is useful in cases where the caller can deal with exceptions such
       as TCL_BREAK or TCL_CONTINUE in a meaningful way.

KEYWORDS
       continue, break, exception, interpreter

Tcl									7.4						    Tcl_AllowExceptions(3)