I do that a lot with the firmware I write in C. typedef struct { err_t error; int error_line; char *error_msg; ... ... } thing_t;

I do that a lot with the firmware I write in C. typedef struct { err_t error; int error_line; char *error_msg; ... ... } thing_t; // set out of range error thing->error = THING_ERROR_OOR; thing->error_line = __LINE__; thing->error_msg = "outofrange" You can grep on 'outofrange' and find where the error was set. I originally started doing that to mark 'bad' analog readings in process control equipment. I wrote my filters and control loops to be able to 'eat' occasional bad readings without barfing. Worked very well.