Using structures

After you define the structure, you can:

• Reference an instance of the structure in scripts
  and functions
• Pass the structure to functions
• Display and paste information about structures by
  using the Browser

Referencing structures

When you define a structure, you are defining a new datatype.
You can use this new datatype in scripts and user-defined functions
as long as the structure definition is stored in a library in the
application’s library search path.

To use a structure in a script or user-defined
function:

1. Declare a variable of the structure type.

2. Reference the variable in the structure.

Referencing global structures

The variables in a structure are similar to the properties
of a PowerBuilder object. To reference a global structure’s
variable, use dot notation:

Example Assume that s_empdata is a global
structure with the variables emp_id, emp_dept, emp_fname, emp_lname,
and emp_salary. To use this structure
definition, declare a variable of type s_empdata and
use dot notation to reference the structure’s variables,
as shown in the following script:

Referencing object-level structures

You reference object-level structures in scripts for the object
itself exactly as you do global structures: declare a variable of
the structure type, then use dot notation:

Example Assume that the structure str_custdata is
defined for the window w_history and
you are writing a script for a CommandButton in the window. To use
the structure definition in the script, you write:

No access to object-level structures outside the object You cannot make object-level structures accessible outside
the object because object-level structures are implicitly private.

Copying structures

To copy the values of a structure to another structure
of the same type:

1. Assign the structure to be copied to the
   other structure using this syntax:

   PowerBuilder

   <i>struct1 = struct2</i>

   1	<i>struct1 = struct2</i>

   PowerBuilder copies all the variable values from struct2 to struct1.

Example These statements copy the values in lstr_emp2 to lstr_emp1:

Using structures with functions

You can pass structures as arguments in user-defined functions.
Simply name the structure as the datatype when defining the argument. Similarly, user-defined
functions can return structures. Name the structure as the return type
for the function.

You can also define external functions that take structures
as arguments.

Example Assume the following:

• Revise is an external
  function that expects a structure as its argument.
• lstr_empdata is a
  declared variable of a structure datatype.

You can call the function as follows:

Declare the function first The external function must be declared before you can reference
it in a script.

For more about passing arguments to external
functions, see Application Techniques
.

Displaying and
pasting structure information

You can display the names and variables of defined structures
in the Browser. You can also paste these entries into a script.

To display information about a global structure
in the Browser:

1. Select the Structure tab and select a structure.

2. Double-click the properties folder in the right
   pane.

   The properties folder expands to show the structure variables
   as properties of the structure.

To display information about an object-level structure
in the Browser:

1. Select the tab for the type of object for
   which the structure is defined.

2. Select the object that contains the structure.

3. Double-click the structure folder in the right
   pane.

   The structure folder expands to display the structure variables
   using dot notation.

To paste the information into a script:

1. Scroll to the structure variable you want
   to paste.

2. Select Copy from the variable’s pop-up
   menu.

3. Insert the cursor in the script where you want
   to paste the variable and select Paste from the pop-up menu.

   The variable name displays at the insertion point in the script.

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