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Tcl_SaveResult(3)                          Tcl Library Procedures                          Tcl_SaveResult(3)



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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_Dis-cardResult Tcl_DiscardResult
       cardResult must be called to properly clean up the memory associated with the saved state.


KEYWORDS
       result, state, interp



Tcl                                                  8.1                                   Tcl_SaveResult(3)