Trace - Revision history

Agember: Fixed code

2007-11-08T20:47:11Z

Fixed code

Agember: Fixed code

2007-11-08T20:46:57Z

Fixed code

Agember: Fixed full implementation code

2007-09-13T22:40:08Z

Fixed full implementation code

Agember: Created article

2007-09-13T22:39:17Z

Created article

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To assist with debugging of XINU [[Modules | modules]] a standard trace interface is currently being implemented across the subsystems. Each module should have its own trace macro of the following form:
#define [MODULE]_TRACE(...) { \
fprintf(TTY1, "%s:%d (%s) ", __FILE__, __LINE__, __FUNCTION__}; \
fprintf(TTY1, __VA_ARGS__); \
fprintf(TTY1, "\n"); }
The trace macro should be defined within the subsystem's main header file. For example, the [[TTY_Driver | TTY driver]] would have the trace macro <code>TTY_TRACE</code> defined in <code>tty.h</code>.

To disable tracing for a particular module, the trace macro definition can be succeeded by:
#undef [MODULE]_TRACE
#define [MODULE]_TRACE
This redefines a particular module's trace macro as nothing, causing the C preprocessor to replace all calls to the module's trace function with nothing. This ability to easily remove trace calls from the module's code will reduce the size of XINU boot image when debugging using trace is not needed.

The overarching <code>XINU_TRACE</code> constant (defined in <code>kernel.h</code>) enables trace for any module with a trace macro defined. To allow all tracing to be disabled at once, each modules trace function should check if <code>XINU_TRACE</code> is defined and only define <code>[MODULE]_TRACE</code> as the trace macro if <code>XINU_TRACE</code> is defined. A full implementation of a <code>[MODULE]_TRACE</code> macro should be:
#ifdef XINU_TRACE
#define [MODULE]_TRACE(...) { \
fprintf(TTY1, "%s:%d (%s) ", __FILE__, __LINE__, __FUNCTION__}; \
fprintf(TTY1, __VA_ARGS__); \
#else
#define [MODULE]_TRACE
#endif

@@ Line 14: / Line 14: @@
    #ifdef XINU_TRACE
      #define [MODULE]_TRACE(...)     { \
-               fprintf(TTY1, "%s:%d (%s) ", __FILE__, __LINE__, __FUNCTION__}; \
+               fprintf(TTY1, "%s:%d (%s) ", __FILE__, __LINE__, __FUNCTION__); \
                fprintf(TTY1, __VA_ARGS__); \
                fprintf(TTY1, "\n"); }