--- a/libmlk-core/mlk/core/trace.h	Sun Mar 05 12:50:11 2023 +0100
+++ b/libmlk-core/mlk/core/trace.h	Sun Mar 05 13:02:07 2023 +0100
@@ -19,21 +19,65 @@
 #ifndef MLK_CORE_TRACE_H
 #define MLK_CORE_TRACE_H
 
+/**
+ * \file mlk/core/trace.h
+ * \brief Non-fatal message logs
+ *
+ * This module provides a simple way to log messages from the API or user code,
+ * mostly when non-fatal errors happened.
+ *
+ * The default implementation uses printf with a timestamp in the form hh:mm::s
+ * to the standard output, it can be disabled using your own
+ * ::mlk_trace_handler or setting it to NULL.
+ *
+ * Example of lines generated by default:
+ *
+ * ```
+ * 10:20:30: hello world
+ * 20:50:00: goodbye world
+ * ```
+ */
+
 #include <stdarg.h>
 
-#define TRACE_LINE_MAX (1024)
+/**
+ * Maximum trace line
+ */
+#define MLK_TRACE_LINE_MAX (128)
 
-extern void (*mlk_trace_handler)(const char *);
+/**
+ * Default trace handler implementation
+ *
+ * Can be set to NULL to disable logging.
+ *
+ * \param line the line to print
+ */
+extern void (*mlk_trace_handler)(const char *line);
 
 #if defined(__cplusplus)
 extern "C" {
 #endif
 
+/**
+ * Write a trace log using a [printf] format style.
+ *
+ * [printf]: https://en.cppreference.com/w/c/io/fprintf
+ *
+ * \pre fmt != NULL
+ * \param fmt the printf format string
+ */
 void
-mlk_tracef(const char *, ...);
+mlk_tracef(const char *fmt, ...);
 
+/**
+ * Similar to ::mlk_tracef but using a `va_list` instead.
+ *
+ * \pre fmt != NULL
+ * \param fmt the printf format string
+ * \param ap the variadic handle
+ */
 void
-mlk_traceva(const char *, va_list);
+mlk_traceva(const char *fmt, va_list ap);
 
 #if defined(__cplusplus)
 }