udfSetError()

This routine allows the user to print out a message and exit the solver if an error is detected. The argument list is the same as that of fprintf(), except that here udfHd takes the place of the file descriptor. For example,

String user_name ;
...
user_name = udfGetName( udfHd ) ;
if ( strcmp(user_name,  "viscosity water") != 0 ) {
   /* compute viscosity for water */
   ...
} else if ( strcmp(user_name, "viscosity air") != 0 ) {
   /* compute viscosity for air */
   ...
} else {
   udfSetError( udfHd, "Invalid user name %s", user_name ) ;
}