C5_PUBLIC

PUBLIC
 Create and initialize public memory variables and arrays
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 Syntax

     PUBLIC <identifier> [[:= <initializer>], ... ]

 Arguments

     <identifier> is the name of a public variable or array to create.
     If the <identifier> is followed by square brackets ([ ]), it is created
     as an array.  If the <identifier> is an array, the syntax for specifying
     the number of elements for each dimension can be array[<nElements>,
     <nElements2>,...] or array[<nElements>][<nElements2>]....  The maximum
     number of elements per dimension is 4096.  The maximum number of
     dimensions per array is limited only by available memory.

     <initializer> is the optional assignment of a value to a new public
     variable.  Array identifiers, however, cannot be given values with an
     <initializer>.  An <initializer> for a public variable consists of the
     inline assignment operator (:=) followed by any valid CA-Clipper
     expression including a literal array.  Except for arrays, if no
     <initializer> is specified, public variables are initialized to false
     (.F.).  This is an exception to the general rule that uninitialized
     variables are NIL.  With arrays, however, the initial value of each
     element is NIL.

     A list of variables and arrays can be created and, optionally,
     initialized with one PUBLIC statement if each definition is separated by
     a comma.

 Description

     The PUBLIC statement creates variables and arrays visible to all
     procedures and user-defined functions in a program.  Public variables
     exist for the duration of the program or until explicitly released with
     CLEAR ALL, CLEAR MEMORY, or RELEASE.  Declaring private, local, or
     static variables or arrays with the same name as existing public
     variables temporarily hides those public variables until the overriding
     variables are released or are no longer visible.  An attempt to create a
     public variable with the same name as an existing and visible private
     variable is simply ignored (see Notes below for an exception).

     Attempting to specify a PUBLIC variable that conflicts with a previous
     FIELD, LOCAL, or STATIC declaration of the same name results in a fatal
     compiler error.  This is true regardless of the scope of the
     declaration.

     PUBLIC statements are executable statements and, therefore, must be
     specified within the body of a procedure or user-defined function
     definition.  They also must follow all compile-time declarations, such
     as FIELD, LOCAL, MEMVAR, and STATIC.

     The maximum number of public and private variables and arrays that can
     simultaneously exist in a single program is 2048.

     For more information on variable declarations and scoping, refer to the
     Variables section in the "Basic Concepts" chapter of the Programming and
     Utilities Guide.

 Notes

     .  PUBLIC Clipper:  To include CA-Clipper extensions in a program
        and still allow the program to run under dBASE III PLUS, the special
        public variable, Clipper, is initialized to true (.T.) when created
        PUBLIC.

     .  Public array name conflicts with existing private variables: 
        The statement, PUBLIC x[10], will not create the public array x if
        there is already a private or public variable x.  It will, however,
        destroy the contents of the existing x, replacing it with a reference
        to a ten-element array.

 Examples

     .  This example creates two PUBLIC arrays and one PUBLIC
        variable:

        PUBLIC aArray1[10, 10], var2
        PUBLIC aArray2[20][10]

     .  The following PUBLIC statements create variables and
        initialize them with values:

        PUBLIC cString := SPACE(10), cColor := SETCOLOR()
        PUBLIC aArray := {1, 2, 3}, aArray2 := ARRAY(12, 24)

See Also: LOCAL MEMVAR PARAMETERS PRIVATE STATIC



3 responses to “C5_PUBLIC

  1. Pingback: Variable Handling | Viva Clipper !

  2. Pingback: C5 Statements | Viva Clipper !

  3. Pingback: C5_STATIC | Viva Clipper !

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