Save last_message as pointer to string

src/include/logging.h

@@ -27,6 +27,10 @@
  * the terminal), as well as to record the execution history in appropriate log
  * files. The `Logger` class offers an implementation of logging system complying
  * with the requirements of the NP_TMcode project.
+ *
+ * The Logger class is designed to work with open files. It is a user responsibility
+ * to check that the required log files are properly opened before use, and closed
+ * thereafter, if they are not the standard `stdout` and `stderr` streams.
  */
 class Logger {
  protected:
@@ -35,7 +39,7 @@ class Logger {
   //! \brief Pointer to logging stream.
   FILE *log_output;
   //! \brief Last logged message.
-  std::string last_message;
+  std::string *last_message;
   //! \brief Threshold of logging level.
   int log_threshold;
   //! \brief Number of identical message repetitions.
@@ -48,13 +52,17 @@ class Logger {
    * be `LOG_DEBG` (log everything), `LOG_INFO` (give detailed information),
    * `LOG_WARN` (log odd looking effects), or `LOG_ERRO` (print error messages,
    * `always active). The default behaviour is `LOG_WARN`.
-   * \param logging_output: `FILE *` Pointer to an output file for common messages
+   * \param logging_output: `FILE *` Pointer to an open output file for common messages
    * (optional, default is `stdout`).
-   * \param error_output: `FILE *` Pointer to an output file for error messages
+   * \param error_output: `FILE *` Pointer to an open output file for error messages
    * (optional, default is `stderr`).
    */
   Logger(int threshold, FILE *logging_output=stdout, FILE *error_output=stderr);
 
+  /*! \brief Logger instance destroyer.
+   */
+  ~Logger();
+
   /*! \brief Print a message to the error output.
    *
    * \param message: `string` The message to be printed.

src/libnptm/logging.cpp

@@ -14,42 +14,56 @@
 using namespace std;
 
 Logger::Logger(int threshold, FILE *logging_output, FILE *error_output) {
-  last_message = "";
+  last_message = new string("");
   log_threshold = threshold;
   log_output = logging_output;
   err_output = error_output;
   repetitions = 0;
 }
 
+Logger::~Logger() {
+  delete last_message;
+}
+
 void Logger::err(std::string message) {
   fprintf(err_output, "%s", message.c_str());
+  fflush(err_output);
 }
 
 void Logger::flush(int level) {
-  string summary = "\"" + last_message + "\" issued " + to_string(repetitions);
+  string summary = "\"" + *last_message + "\" issued " + to_string(repetitions);
   if (repetitions == 1) summary += " time.\n";
   else summary += " times.\n";
   if (level == LOG_ERRO) err(summary);
   else {
-    if (level >= log_threshold) fprintf(log_output, "%s", summary.c_str());
+    if (level >= log_threshold) {
+      fprintf(log_output, "%s", summary.c_str());
+      fflush(log_output);
+    }
   }
+  delete last_message;
+  last_message = new string("");
   repetitions = 0;
 }
 
 void Logger::log(std::string message, int level) {
   if (level == LOG_ERRO) err(message);
   else {
-    if (level >= log_threshold) fprintf(log_output, "%s", message.c_str());
+    if (level >= log_threshold) {
+      fprintf(log_output, "%s", message.c_str());
+      fflush(log_output);
+    }
   }
 }
 
 void Logger::push(std::string message) {
   if (repetitions > 0) {
-    if (message.compare(last_message) != 0) {
+    if (message.compare(*last_message) != 0) {
       flush(LOG_DEBG);
     }
   }
   log(message, LOG_DEBG);
-  last_message = message;
+  delete last_message;
+  last_message = new string(message);
   repetitions++;
 }