MIDL Compiler Errors and Warnings
When using the MIDL compiler, errors and warnings can be caused by improper use of the command-line switches or by the content of the IDL and ACF files. If the error is due to improperly entering the command-line switches, an error or warning message may specify the name of one or more MIDL compiler mode switches. For example, you can include certain ACF attributes in an IDL file when you use the /app_config switch, but that IDL file will generate an error if you compile without using the /app_config switch.
Errors in the IDL and ACF files fall into two categories: errors caught by the preprocessor and errors recognized by the compiler. This section lists the MIDL preprocessor and compiler error messages. It also describes their formats and causes.