trusty (3) Tcl_SetBooleanObj.3tcl.gz

NAME

       Tcl_NewBooleanObj, Tcl_SetBooleanObj, Tcl_GetBooleanFromObj - manipulate 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
                                        interpreter's result object unless interp is NULL.

       int          *boolPtr  (out)     Points  to place where Tcl_GetBooleanFromObj stores the boolean value (0
                                        or 1) obtained from objPtr.
_________________________________________________________________

DESCRIPTION

       These procedures are used to create, modify, and read boolean Tcl objects from C code.  Tcl_NewBooleanObj
       and  Tcl_SetBooleanObj  will  create  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 procedures 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 representation.

       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