Use Highs::closeLogFile in destructor

Author: jajhall

highs/Highs.h

@@ -46,11 +46,9 @@ class Highs {
     FILE* log_stream = this->options_.log_options.log_stream;
     if (log_stream != nullptr) {
       assert(log_stream != stdout);
-      // Was this, but only passing a copy of the pointer, so not
-      // closing the true log stream?
-      //
-      // fclose(log_stream);
-      fclose(this->options_.log_options.log_stream);
+      // Flush and close log_stream
+      fflush(log_stream);
+      fclose(log_stream);
     }
   }
 

highs/lp_data/Highs.cpp

@@ -4763,20 +4763,16 @@ HighsStatus Highs::openLogFile(const std::string& log_file) {
 }
 
 HighsStatus Highs::closeLogFile() {
+  // Work with a copy of the pointer for brevity
   FILE* log_stream = this->options_.log_options.log_stream;
   if (log_stream != nullptr) {
     assert(log_stream != stdout);
-    // Using this, as in the original destructor of Highs, only
-    // passing a copy of the pointer, so not closing the true log
-    // stream?
-    //
-    // fclose(log_stream);
-    fclose(this->options_.log_options.log_stream);
-    // Set log_stream to nullptr to give a test whether the it has
-    // been closed (and avoid trying to close it again which causes an
-    // error).
+    fflush(log_stream);
+    fclose(log_stream);
+    // Set the true log_stream to nullptr to give a test whether it
+    // has been closed (and avoid trying to close it again which
+    // causes an error)
     this->options_.log_options.log_stream = nullptr;
-    assert(this->options_.log_options.log_stream == nullptr);
   }
   return HighsStatus::kOk;
 }

highs/lp_data/HighsOptions.cpp

@@ -25,19 +25,22 @@ void highsOpenLogFile(HighsLogOptions& log_options,
   OptionStatus status =
       getOptionIndex(log_options, "log_file", option_records, index);
   assert(status == OptionStatus::kOk);
-  if (log_options.log_stream != NULL) {
+  if (log_options.log_stream != nullptr) {
     // Current log file stream is not null, so flush and close it
     fflush(log_options.log_stream);
     fclose(log_options.log_stream);
+    // Set the stream to null to give a test whether it has been
+    // closed (and avoid trying to close it again which causes an
+    // error)
+    log_options.log_stream = nullptr;
   }
-  if (log_file.compare("")) {
-    // New log file name is not empty, so open it, appending if
-    // possible
+  assert(!log_options.log_stream);
+  // If new log file name is not empty, open it, appending if possible
+  //
+  // If fopen fails then it returns nullptr, so log_file is open for
+  // writing or nullptr
+  if (log_file.compare(""))
     log_options.log_stream = fopen(log_file.c_str(), "a");
-  } else {
-    // New log file name is empty, so set the stream to null
-    log_options.log_stream = NULL;
-  }
   OptionRecordString& option = *(OptionRecordString*)option_records[index];
   option.assignvalue(log_file);
 }