At my last company I had a global variable containing the current error message (much like errno, only a descriptive string rather than an integer). Whenever an error was detected, I would set it to an appropriate message and return -1. A caller would detect the failure and print out the global error descriptor. (This was in C, btw.)

When running under the debugger, it was useful to have an easily recognizable value that would indicate that no error had happened yet, so I initialized it to "Life is good".

Unsurprisingly, I ended up with a number of routines that didn't bother to set the error message, but still returned -1. So it became fairly common to see messages like:

Fatal error, unable to continue: Life is good