How do I redefine an fprintf function as a tracing call?

An fprintf function call, which is eventually converted to an sprintf function call, is a very resource-intensive call that can degrade performance perceptibly, especially when it is used repeatedly.

Redefining an fprintf function as a tracing call is much more efficient, because the trace messages are stored in binary format and formatting is postponed until you display the trace log.

To redefine a printing function such as fprintf as a tracing call, the resulting call must do two things:

  • Assign a default level for the tracing function, such as error, warning, or noise.

  • Ignore the handle.

The following example shows a function description that does both:


You can define this function description in a local configuration file, such as localwpp.ini, or use the -func parameter of RUN_WPP (the macro that invokes the WPP preprocessor) to define the function description.

For a complete list of the optional parameters for RUN_WPP, see WPP Preprocessor.

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