The TRACE macros are obsolete, use ATLTRACE2.
TRACE0 is similar to TRACE and is one variant of a group of trace macros that you can use for debug output.
The group includes:
TRACE0 Takes a format string (Only) and can be used for simple text messages, which are dumped to afxDump.
TRACE1 Takes a format string plus one argument (one variable that is dumped to afxDump).
TRACE2 Takes a format string plus two arguments (two variables that are dumped to afxDump).
TRACE3 Takes a format string plus three arguments (three variables that are dumped to afxDump).
TRACE0 does nothing if you have compiled a release version of your application. As with TRACE, it only dumps data to afxDump if you have compiled a debug version of your application.
This macro is available only in the debug version of MFC.
// Example for TRACE0 TRACE0( "Start Dump of MyClass members:" ); // Another example for TRACE0 // This works, but it is easier to use TRACE() or TRACE1() DWORD dwLastError = ::GetLastError(); CString str; str.Format("The last error code for this thread is %d\n", dwLastError); TRACE0( (LPCTSTR) str); // These are all normal uses of TRACE0() TRACE0("This message will be output. "); TRACE0("This text is on the same line.\n"); TRACE0("This text is on the next line.\n");