Clalev

clalev allows you to know if a class (usually a table associated class) can be accessed in a given context.

Syntax

   clalev(CLASS_DESCRIPTION)
   clalev(NUMERIC_EXPRESSION)

• CLASS_DESCRIPTION is a class description with the [ABBR] syntax, where ABBR is the abbreviation of a class.
• NUMERIC_EXPRESSION refers to the slot number for the class. This can be seen in the debugger, but should be considered rather as internal.

Examples

  # List of the classes available in the current context
  Local Integer MAXCLA,I,J
    MAXCLA = 200
  Local Char CLASS_NAMES(20)(1..MAXCLA)
    For I = 1 To MAXCLA
       If clalev(I) <> 0
          J+=1
          CLASS_NAMES(J)=clanam(I)
       Endif
    Next I
  # If the [ORDER] table opened
  If clalev([ORDER])
    # The table is already opened
  Else
    # The table is not opened
  Endif

Description

clalev allows you to determine if a class with a given abbreviation is available.

The result of the function is an integer value of 1 (if the class is available) or 0 (if the class is not available).

Comments

This function was used in version 6 programming to avoid re-opening an already opened table. In version 7, it is deprecated because opening a table has been optimized and also because not opening a table can cause conflicts.

You can still use it when a common subprogram is supposed to use an already opened class, and open it if it is not the case.

Associated errors

Error	Description
50	The numeric argument is negative.

See also

clanam, clasiz, clanbs, clavar.