[Positioning] TextFileWriter throws error_opening_output_file

Fix mistake in TextFileWriter::TextFileWriter(), that thrown
error_opening_input_file instead of error_opening_output_file.
Creation of class error_opening_output_file in posexcept.

owlps-positioning/src/posexcept.cc

@@ -119,6 +119,19 @@ const char* no_output_csv_file::what() const throw()
 }
 
 
+error_opening_output_file::
+error_opening_output_file(const string &_file_name) throw():
+  file_name(_file_name) {}
+
+
+const char* error_opening_output_file::what() const throw()
+{
+  string message = "Error opening output file « " +
+                   file_name + " »!" ;
+  return message.c_str() ;
+}
+
+
 
 /* *** Algorithms *** */
 

owlps-positioning/src/posexcept.hh

@@ -116,6 +116,18 @@ public:
 } ;
 
 
+class error_opening_output_file: public posexcept
+{
+private:
+  std::string file_name ;
+
+public:
+  error_opening_output_file(const std::string &_file_name) throw() ;
+  ~error_opening_output_file(void) throw() {}
+  const char* what(void) const throw() ;
+} ;
+
+
 
 /* *** Algorithms *** */
 

owlps-positioning/src/textfilewriter.cc

@@ -17,7 +17,7 @@ TextFileWriter::TextFileWriter(const string &_file_name):
 {
   file.open(file_name.c_str()) ;
   if (! file)
-    throw error_opening_input_file(file_name) ;
+    throw error_opening_output_file(file_name) ;
 }