PUBLIC

PUBLIC

Create and initialize public memory variables and arrays

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 Harbour 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.

Notes

. 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)

Seealso

LOCAL, MEMVAR, PARAMETERS, PRIVATE, STATIC

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One response to “PUBLIC

  1. Pingback: Harbour Statements | Viva Clipper !

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