The TRACE Macro
This topic explains how to use the TRACE macro during development to print or display debugging messages from a program. TRACE prints a string argument to your debugger.
Note With 32-bit MFC, the only way to get debug output is via the debugger.
The TRACE macro can handle a variable number of arguments, similar to the way printf operates. Following are examples of different ways to use TRACE macros:
int x = 1; int y = 16; float z = 32.0; TRACE( "This is a TRACE statement\n" ); TRACE( "The value of x is %d\n", x ); TRACE( "x = %d and y = %d\n", x, y ); TRACE( "x = %d and y = %x and z = %f\n", x, y, z );
The TRACE macro is active only in the debug version of the class library. After a program has been debugged, you can build a release version to deactivate all TRACE calls in the program.
Tip When debugging Unicode, the TRACE0, TRACE1, TRACE2, and TRACE3 macros are easier to use because the _T macro is not needed.
For important information on the TRACE macro, see in the Class Library Reference and .