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 inter-
                                              preter 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 rou-
       tines 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 inter-
       preter 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(3)