1 The message parameters are:
     2  - <b>file</b> which should be the __FILE__ macro
     3  - <b>line</b> which should be the __LINE__ macro
     4  - <b>code_errno</b> which should be the errno value, or 0 
if not relevant 
     5  - <b>code_other</b> which should a non-errno code 
if relevant, 0 otherwise.
     6  - <b>expl which</b> is an explanation of the error.  Can be empty.
     8 software_log::messageT constructors are provided with combinations of the parameters.  Some examples:
    10 log<software_error>({__FILE__, __LINE__, errno, retval, 
"an error occurred"}); 
    13 log<software_error>({__FILE__, __LINE__, errno); 
    16 log<software_info>({__FILE__, __LINE__, 
"a directory was created"}); 
    19 log<software_debug>({__FILE__, __LINE__});