The primary reason to write your own API program is to satisfy a requirement that you cannot accomplish with the AR System clients. In addition, API programming gives you flexibility to customize your application.
However, API solutions are more complex to design, implement, and maintain. If you write an API program, you must manage all cross-platform issues and issues related to AR System upgrades. See Migrating-to-the-current-release-of-AR-System-C-API for information about changes to the API for version 9.1 and later.
You might want to write an API program if:
You need to access multiple AR System components at the same time or integrate with programs or data outside the AR System.
You need to perform complex operations that involve multiple forms.
You need a two-way interface (or gateway) between AR System and another application.
The values that you need to specify for $PROCESS$ or the Run Process action (see Creating-and-executing-AR-System-C-API-programs) exceed the size limitation of the command line. On some systems, for example, the command-line area for $PROCESS$ or Run Process parameters is limited to 256 bytes (expandable to 4 KB). If you use an API program instead, you can pass a parameter to an API program and manipulate larger-sized data within the program.
You need to create reports or log files in a format that is not compatible with standard report writing tools.