Variant of a group of trace macros that you can use for debug output.
A format string as used in the run-time function printf.
This group includes ISAPITRACE0, ISAPITRACE1, ISAPITRACE2, and ISAPITRACE3. The difference between these macros is the number of parameters taken. ISAPITRACE0 only takes a format string and can be used for simple text messages. ISAPITRACE1 takes a format string plus one argument — a variable to be dumped. Likewise, ISAPITRACE2 and ISAPITRACE3 take two and three parameters after the format string, respectively.
ISAPITRACE0 does nothing if you have compiled a release version of your application. As with ISAPITRACE, it only dumps data to the debug output device if you have compiled a debug version of your application.
ISAPITRACE0 works exactly like the MFC macro TRACE0. ISAPI applications do not have to use MFC. If MFC is not linked to your application, ISAPITRACE0 provides the same TRACE0 functionality. If your application is linked to the MFC, ISAPITRACE0 simply calls MFC's TRACE0.