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Full Discussion: Checking an array for NULL in C++
Top Forums Programming Checking an array for NULL in C++ Post 302543987 by Corona688 on Tuesday 2nd of August 2011 03:33:57 PM
Old 08-02-2011
Quote:
Originally Posted by mind@work
Actually ...wt. I had to check was that if the char pointer has a string initialized or it is not yet initialized.
To check if a string is zero length is easy even without a function call.
Code:
if(str[0] == '\0')

But uninitialized doesn't mean zero length, uninitialized means undefined. That means empty only if you're lucky. If you're unlucky it could be full of garbage. Don't check if a string is uninitialized -- don't leave around uninitialized strings, period.
 

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LEARN ABOUT OPENDARWIN

tcl_discardresult

Tcl_SaveResult(3)					      Tcl Library Procedures						 Tcl_SaveResult(3)

__________________________________________________________________________________________________________________________________________________

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.
_________________________________________________________________

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 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  can-
       not 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)
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