In CP2K there exist three convenient macros for error handling. They are defined in cp2k/src/common/cp_common_uses.f90, and are therefore always available. However, these macros can only be used for short messages, because of Fortran's line length limitation.

   CPWARN("A short warning message")
   CPABORT("A short error message")
   CPASSERT(2>1) ! For sanity checks only, not for user errors.

For longer messages one can use these two routines:

   CALL cp_warn(__SHORT_FILE__,__LINE__,"A long warning message "\\&
                "which can span multiple lines and contains "\\&
                "some valuable advice for the user.")
 
   CALL cp_abort(__SHORT_FILE__,__LINE__,"A long error message "\\&
                 "with even more valuable advises.")