Constants

A constant is a named item that retains its value throughout all operations. The value π, or 3.1415926535, is an example of a numeric constant; the letter A is an example of a character constant.

You can create compile-time constants that exist throughout the operation of a Visual FoxPro application. You can use a constant and know that its value doesn't change during the operation of your application. At design time, you can effect a change throughout an application by changing only the value of a single constant.

A constant can contain any data type value.

To assign a value to a constant

• Use the #DEFINE preprocessor directive.

In the following example, the constant TABLERR1 is defined as a character string.

#DEFINE TABLERR1 "This table is not available. Please try later."

In an application, wherever you would normally specify the character string "This table is not available. Please try later." you can use TABLERR1 instead.

To release a defined constant

• Use the #UNDEFINE preprocessor directive.

  #UNDEF TABLERR1
  

See Also

Variables | #DEFINE ... #UNDEF Preprocessor Directive | PI( ) Function | Constant is already created with #DEFINE (Error 1725) | #IFDEF | #IFNDEF ... #ENDIF Preprocessor Directive | Data Storage Containers