Q40680: Why #ifdef and #ifndef Are Used in PGCHART.H

Article: Q40680
Product(s): See article
Version(s): 2.00
Operating System(s): MS-DOS
Keyword(s): ENDUSER | | mspl13_c
Last Modified: 28-FEB-1989

The header file PGCHART.H, which is required for programs using QuickC
2.00's Presentation Graphics, contains many #ifdef and #ifndef
preprocessor commands. This include file has these commands so you
will not get warnings or errors if you happen to include the file more
than once.

These commands are provided in all of the include files where
structures (or types) are typedef'ed; it is just a little more obvious
in PGCHART.H because it defines so many structures.