Tcl_NewBooleanObj(3)

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NAME

       Tcl_NewBooleanObj,  Tcl_SetBooleanObj,  Tcl_GetBooleanFromObj - manipu-
       late Tcl objects as boolean values

SYNOPSIS

       #include <tcl.h>

       Tcl_Obj *
       Tcl_NewBooleanObj(boolValue)

       Tcl_SetBooleanObj(objPtr, boolValue)

       int
       Tcl_GetBooleanFromObj(interp, objPtr, boolPtr)

ARGUMENTS

       int          boolValue (in)      Integer value used  to  initialize  or
                                        set  a boolean object.  If the integer
                                        is nonzero, the boolean object is  set
                                        to  1; otherwise the boolean object is
                                        set to 0.

       Tcl_Obj      *objPtr   (in/out)  For Tcl_SetBooleanObj, this points  to
                                        the  object to be converted to boolean
                                        type.  For Tcl_GetBooleanFromObj, this
                                        refers to the object from which to get
                                        a boolean value; if  objPtr  does  not
                                        already  point to a boolean object, an
                                        attempt will be made to convert it  to
                                        one.

       Tcl_Interp   *interp   (in/out)  If  an error occurs during conversion,
                                        an error message is left in the inter-
                                        preter's  result  object unless interp
                                        is NULL.

       int          *boolPtr  (out)     Points to place where  Tcl_GetBoolean-
                                        FromObj stores the boolean value (0 or
                                        1) obtained from objPtr.
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DESCRIPTION

       These procedures are used to  create,  modify,  and  read  boolean  Tcl
       objects from C code.  Tcl_NewBooleanObj and Tcl_SetBooleanObj will cre-
       ate a new object of boolean type or modify an existing object  to  have
       boolean  type.   Both  of  these  procedures set the object to have the
       boolean value (0 or 1) specified by boolValue; if boolValue is nonzero,
       the  object  is  set to 1, otherwise to 0.  Tcl_NewBooleanObj returns a
       pointer to a newly created object with reference count zero.  Both pro-
       cedures  set  the  object's  type  to be boolean and assign the boolean
       value  to  the  object's  internal  representation  longValue   member.
       Tcl_SetBooleanObj invalidates any old string representation and, if the
       object is not already a boolean object, frees any old  internal  repre-
       sentation.

       Tcl_GetBooleanFromObj  attempts  to return a boolean value from the Tcl
       object objPtr.  If the object is not already a boolean object, it  will
       attempt to convert it to one.  If an error occurs during conversion, it
       returns TCL_ERROR and leaves an  error  message  in  the  interpreter's
       result  object unless interp is NULL.  Otherwise, Tcl_GetBooleanFromObj
       returns TCL_OK and stores the boolean value in  the  address  given  by
       boolPtr.  If the object is not already a boolean object, the conversion
       will free any old internal representation.   Objects  having  a  string
       representation  equal  to  any  of  0, false, no, or off have a boolean
       value 0; if the string representation is any of 1, true, yes, or on the
       boolean value is 1.  Any of these string values may be abbreviated, and
       upper-case spellings are also acceptable.

SEE ALSO

       Tcl_NewObj, Tcl_DecrRefCount, Tcl_IncrRefCount, Tcl_GetObjResult

KEYWORDS

       boolean, boolean object, boolean type, internal representation, object,
       object type, string representation

Tcl                                   8.0                    Tcl_BooleanObj(3)