From fac48bdb175f773322318a9bf15551706717582f Mon Sep 17 00:00:00 2001
From: Wolfgang Bangerth <bangerth@colostate.edu>
Date: Mon, 24 Feb 2020 14:59:08 -0700
Subject: [PATCH] Avoid using std::endl over '\n'.

std::endl writes an endline character into the stream, but then follows
that up with a flush(). That's expensive on remote-mounted file systems,
and most unnecessary as well -- we should really just write the endline
character and put a flush() at the very end of the operation.
---
 source/base/table_handler.cc | 41 ++++++++++++++++++++----------------
 1 file changed, 23 insertions(+), 18 deletions(-)

diff --git a/source/base/table_handler.cc b/source/base/table_handler.cc
index 1d24d9b08b..c25053d5da 100644
--- a/source/base/table_handler.cc
+++ b/source/base/table_handler.cc
@@ -433,7 +433,7 @@ TableHandler::write_text(std::ostream &out, const TextOutputFormat format) const
               out << std::setw(column_widths[j]);
               out << key << " | ";
             }
-          out << std::endl;
+          out << '\n';
 
           // write the body
           for (unsigned int i = 0; i < nrows; ++i)
@@ -602,14 +602,14 @@ TableHandler::write_tex(std::ostream &out, const bool with_header) const
   // write_text() to use the cache
   AssertThrow(out, ExcIO());
   if (with_header)
-    out << "\\documentclass[10pt]{report}" << std::endl
-        << "\\usepackage{float}" << std::endl
-        << std::endl
-        << std::endl
-        << "\\begin{document}" << std::endl;
-
-  out << "\\begin{table}[H]" << std::endl
-      << "\\begin{center}" << std::endl
+    out << "\\documentclass[10pt]{report}" << '\n'
+        << "\\usepackage{float}" << '\n'
+        << '\n'
+        << '\n'
+        << "\\begin{document}" << '\n';
+
+  out << "\\begin{table}[H]" << '\n'
+      << "\\begin{center}" << '\n'
       << "\\begin{tabular}{|";
 
   // first pad the table from below if necessary
@@ -657,7 +657,7 @@ TableHandler::write_tex(std::ostream &out, const bool with_header) const
           out << col_iter->second.tex_format << "|";
         }
     }
-  out << "} \\hline" << std::endl;
+  out << "} \\hline" << '\n';
 
   // write the caption line of the table
 
@@ -673,7 +673,7 @@ TableHandler::write_tex(std::ostream &out, const bool with_header) const
           // avoid use of `tex_supercaptions[key]'
           std::map<std::string, std::string>::const_iterator
             tex_super_cap_iter = tex_supercaptions.find(key);
-          out << std::endl
+          out << '\n'
               << "\\multicolumn{" << n_subcolumns << "}{|c|}{"
               << tex_super_cap_iter->second << "}";
         }
@@ -688,7 +688,7 @@ TableHandler::write_tex(std::ostream &out, const bool with_header) const
       if (j < column_order.size() - 1)
         out << " & ";
     }
-  out << "\\\\ \\hline" << std::endl;
+  out << "\\\\ \\hline" << '\n';
 
   // write the n rows
   const unsigned int nrows = n_rows();
@@ -718,20 +718,25 @@ TableHandler::write_tex(std::ostream &out, const bool with_header) const
           if (j < n_cols - 1)
             out << " & ";
         }
-      out << "\\\\ \\hline" << std::endl;
+      out << "\\\\ \\hline" << '\n';
     }
 
-  out << "\\end{tabular}" << std::endl << "\\end{center}" << std::endl;
+  out << "\\end{tabular}" << '\n' << "\\end{center}" << '\n';
   if (!tex_table_caption.empty())
-    out << "\\caption{" << tex_table_caption << "}" << std::endl;
+    out << "\\caption{" << tex_table_caption << "}" << '\n';
   if (!tex_table_label.empty())
-    out << "\\label{" << tex_table_label << "}" << std::endl;
-  out << "\\end{table}" << std::endl;
+    out << "\\label{" << tex_table_label << "}" << '\n';
+  out << "\\end{table}" << '\n';
   if (with_header)
-    out << "\\end{document}" << std::endl;
+    out << "\\end{document}" << '\n';
+
+  // Now flush all of the data we've put into the stream to make it
+  // sure it really gets written.
+  out << std::flush;
 }
 
 
+
 void
 TableHandler::clear()
 {
-- 
2.39.5