add function comments

logging.h

@@ -12,10 +12,42 @@
 #define LOG_WARN 2
 #define LOG_ERROR 3
 
+/**
+ * Sets the global log level for the logger.
+ *
+ * @param level The log level to set. Possible values are LOG_DEBUG, LOG_INFO,
+ * LOG_WARN, and LOG_ERROR. Messages below this level will not be logged.
+ */
 void set_log_level(int level);
 
-void log_message(int level, const char* fmt, ...);
-
+/**
+ * Opens the log file for appending log messages.
+ *
+ * @details
+ * This function attempts to open the log file specified by LOG_FILE_NAME
+ * in append mode. If the file cannot be opened, an error message is printed
+ * to stderr.
+ */
 void open_log_file();
 
-void close_log_file();
+/**
+ * Close the log file if it is open. This should be called when the program is
+ * about to exit to ensure that the log file is properly closed.
+ *
+ * @details
+ * If the log file is not open, this function does nothing.
+ */
+void close_log_file();
+
+/**
+ * Logs a message with the given level and format string to the console and to
+ * the log file. If the level is less than the current log level, the message is
+ * not logged. The message is formatted according to fmt and varargs, and is
+ * prefixed with a timestamp and a string corresponding to the log level.
+ *
+ * @param level The log level to log the message at. Possible values are
+ * LOG_DEBUG, LOG_INFO, LOG_WARN, and LOG_ERROR.
+ * @param fmt The format string for the message to log
+ * @param ... The variadic arguments to format the string with
+ */
+void log_message(int level, const char* fmt, ...);