Страницы справочника OS X

Эта страница руководства является частью версии 5.0 Инструментов XCode

Читать страницы руководства

Tcl_ExprLongObj(3)                         Tcl Library Procedures                         Tcl_ExprLongObj(3)



____________________________________________________________________________________________________________

NAME
       Tcl_ExprLongObj, Tcl_ExprDoubleObj, Tcl_ExprBooleanObj, Tcl_ExprObj - evaluate an expression

SYNOPSIS
       #include <tcl.h>

       int
       Tcl_ExprLongObj(interp, objPtr, longPtr)

       int
       Tcl_ExprDoubleObj(interp, objPtr, doublePtr)

       int
       Tcl_ExprBooleanObj(interp, objPtr, booleanPtr)

       int
       Tcl_ExprObj(interp, objPtr, resultPtrPtr)

ARGUMENTS
       Tcl_Interp *interp (in)                 Interpreter in whose context to evaluate objPtr.

       Tcl_Obj *objPtr (in)                    Pointer to an object containing the expression to evaluate.

       long *longPtr (out)                     Pointer  to  location  in which to store the integer value of
                                               the expression.

       int *doublePtr (out)                    Pointer to location in  which  to  store  the  floating-point
                                               value of the expression.

       int *booleanPtr (out)                   Pointer  to  location in which to store the 0/1 boolean value
                                               of the expression.

       Tcl_Obj **resultPtrPtr (out)            Pointer to location in which to store a pointer to the object
                                               that is the result of the expression.
____________________________________________________________________________________________________________


DESCRIPTION
       These  four  procedures  all  evaluate  an  expression, returning the result in one of four different
       forms.  The expression is given by the objPtr argument, and it can have any of the forms accepted  by
       the expr command.

       The  interp argument refers to an interpreter used to evaluate the expression (e.g. for variables and
       nested Tcl commands) and to return error information.

       For all of these procedures the return value is a standard Tcl result: TCL_OK  means  the  expression
       was  successfully  evaluated, and TCL_ERROR means that an error occurred while evaluating the expres-sion. expression.
       sion.  If TCL_ERROR is returned, then a message describing the error can be retrieved using Tcl_GetO-bjResult. Tcl_GetObjResult.
       bjResult.   If  an  error  occurs  while executing a Tcl command embedded in the expression then that
       error will be returned.

       If the expression is successfully evaluated, then its value is returned in one of four forms, depend-ing depending
       ing  on  which  procedure  is  invoked.  Tcl_ExprLongObj stores an integer value at *longPtr.  If the
       expression's actual value is a floating-point number, then it is truncated to  an  integer.   If  the
       expression's actual value is a non-numeric string then an error is returned.

       Tcl_ExprDoubleObj  stores  a floating-point value at *doublePtr.  If the expression's actual value is
       an integer, it is converted to floating-point.  If the expression's actual  value  is  a  non-numeric
       string then an error is returned.

       Tcl_ExprBooleanObj stores a 0/1 integer value at *booleanPtr.  If the expression's actual value is an
       integer or floating-point number, then they store 0 at *booleanPtr if the value was zero and 1 other-wise. otherwise.
       wise.   If  the  expression's  actual value is a non-numeric string then it must be one of the values
       accepted by Tcl_GetBoolean such as "yes" or "no", or else an error occurs.

       If Tcl_ExprObj successfully evaluates the expression, it stores a pointer to the Tcl object  contain-ing containing
       ing  the  expression's  value  at *resultPtrPtr.  In this case, the caller is responsible for calling
       Tcl_DecrRefCount to decrement the object's reference count when it is finished with the object.


SEE ALSO
       Tcl_ExprLong, Tcl_ExprDouble, Tcl_ExprBoolean, Tcl_ExprString, Tcl_GetObjResult


KEYWORDS
       boolean, double, evaluate, expression, integer, object, string



Tcl                                                  8.0                                  Tcl_ExprLongObj(3)