When the system validation function finds that the user has entered an invalid response in a field, the function sets an error code. The form editor responds by setting the error window on the screen and displaying an error message.
A default error window is initially defined in vv_init() as window with no border. The error window covers the last row of the screen, and the logical attribute of the window is LERROR. The pointer to this window is #defined as ERR_WNP. When a form is defined, the pointer to ERR_WNP is copied to one of the form structure members.
Designer: You cannot change the error window from within the Designer; you must change it in your code.
Code: You can use any of the window functions discussed in Chapter 25, "Changing the Appearance of Windows," to modify the error window ERR_WNP.
For example, to change the attribute of the error window, call:
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To make a two-line error window, call:
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After making these changes, the error window for all forms in your application will be displayed with these properties.
Note: vs_rowq() and vs_colq() are functions that return the number of rows and columns, respectively, for the screen.
General: Note that each form does not have its own copy of the error window. Since each form points to the same error window, any modifications you make to ERR_WNP will affect the error window for all forms in your application. However, you can define a new error window for a specific form by calling wn_def() and storing the returned pointer in the error window member of the form structure. You can then modify that error window without affecting the error window used for other forms.
