Improved the comments surrounding strerror_r_wrapper()

mediachanger/castorrmc/common/strerror_r_wrapper.cpp

@@ -39,5 +39,15 @@
  * strerror_r_wrapper
  ******************************************************************************/
 extern "C" int strerror_r_wrapper(int errnum, char *buf, size_t buflen) {
+  /* This function should be compiled using a C++ compiler and not a C compiler.
+   *
+   * C++ compilers are better at spotting whether the GNU version or the
+   * XSI complicant version of sterror_() is being used. This is because the
+   * difference between the two versions is their return types.  The GNU
+   * version returns a 'char *' whereas the XSI compliant version returns an
+   * 'int'.  A C compiler may allow the strerror_r() function to return a
+   * 'char *' and have that 'char *' assigned to an 'int'.  A C++ compiler
+   * usually gives an error if this is tried.
+   */
   return strerror_r(errnum, buf, buflen);
 }

mediachanger/castorrmc/h/strerror_r_wrapper.h

@@ -44,6 +44,16 @@
  * This function wraps the XSI compliant version of strerror_r() and therefore
  * writes the string representation of the specified error number to the
  * specified buffer.
+ *
+ * This function should be compiled using a C++ compiler and not a C compiler.
+ *
+ * C++ compilers are better at spotting whether the GNU version or the
+ * XSI complicant version of sterror_() is being used. This is because the
+ * difference between the two versions is their return types.  The GNU
+ * version returns a 'char *' whereas the XSI compliant version returns an
+ * 'int'.  A C compiler may allow the strerror_r() function to return a
+ * 'char *' and have that 'char *' assigned to an 'int'.  A C++ compiler
+ * usually gives an error if this is tried.
  * 
  * @param errnum The error number.
  * @param buf The buffer.