The information in the following sections discuss whether or not each error is considered to be recoverable. This refers to the recommended action for a program should take when the error is reported, and does not refer to the status of DP4 databases. Recovering from DP4 errors is only possible in programs that use the DP4 interface using C or C++. Standard DP4 utilities will usually terminate when one of these errors is reported. If you are a programmer and are attempting to catch and continue execution after of one of these errors, you need to be careful to guard against the possibility of an endless succession of error messages.
Generic DP4 error messages fall into three main categories. If you want to find out more about a particular error it is important to know which category it comes from, because the same error number may exist in several categories, with a different meaning in each.
DP4 System errors are either displayed using maps from the SYSTEM mapset on the SYSTEM database, or, from 4.620, text held in the DP4 configuration file.
DP4 Fail Errors are held in and displayed by the FAIL program. Fail errors are often caused by an error reported by the operating system, and in this case the message from the operating system will be displayed as well. From 4.620 the FAIL program is not used to display these errors, and the text is held in the DP4 configuration file.
Loader errors, currently specific to Windows, are displayed by the DP4 loader program (srvw32 or srvwce) when there is a problem starting or stopping the DP4 service. The text is taken from the DP4 configuration file.
All standard DP4 utilities report errors using the sources of error text described above. However, programs that use DP4 might not report errors in a standard way if they attempt to handle errors. However, if DP4 error logging is turned on and the debug_error setting value is true, DP4 will always additionally report errors to the error log in numeric form. The exact format of the report will vary in this case, but you can still determine the DP4 error message. This is explained in Interpreting DP4 Error log Error Messages.