NAME

       Tcl_SaveResult, Tcl_RestoreResult, Tcl_DiscardResult - save and restore an interpreter's result

SYNOPSIS

       #include <tcl.h>

       Tcl_SaveResult(interp, statePtr)

       Tcl_RestoreResult(interp, statePtr)

       Tcl_DiscardResult(statePtr)

ARGUMENTS

       Tcl_Interp        *interp    (in)      Interpreter for which state should be saved.

       Tcl_SavedResult   *statePtr  (in)      Pointer  to  location  where interpreter result should be saved or
                                              restored.
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DESCRIPTION

       These routines allows a C procedure to take a snapshot of the current interpreter result so that  it  can
       be  restored  after a call to Tcl_Eval or some other routine that modifies the interpreter result.  These
       routines are passed a pointer to a structure that is used to store  enough  information  to  restore  the
       interpreter  result state.  This structure can be allocated on the stack of the calling procedure.  These
       routines do not save the state of any error  information  in  the  interpreter  (e.g.  the  errorCode  or
       errorInfo variables).

       Tcl_SaveResult  moves  the  string  and object results of interp into the location specified by statePtr.
       Tcl_SaveResult clears the result for interp and leaves the result in its normal empty initialized state.

       Tcl_RestoreResult moves the string and object results from statePtr back  into  interp.   Any  result  or
       error  that  was  already  in  the interpreter will be cleared.  The statePtr is left in an uninitialized
       state and cannot be used until another call to Tcl_SaveResult.

       Tcl_DiscardResult releases the saved interpreter state stored at statePtr.  The state structure  is  left
       in an uninitialized state and cannot be used until another call to Tcl_SaveResult.

       Once   Tcl_SaveResult   is   called   to   save  the  interpreter  result,  either  Tcl_RestoreResult  or
       Tcl_DiscardResult must be called to properly clean up the memory associated with the saved state.

KEYWORDS

       result, state, interp

Tcl                                                    8.1                                  Tcl_SaveResult(3tcl)